As the title says, JUST got Skyrim off STEAM. I keep hearing about mods...
Which ones are a MUST have and how do I apply them?
The only must haves are the unofficial patches. Plus, you want SKSE+SkyUI, even with no added mods.
Use Nexus Mod Manager, Wrye Bash (if you're an old school Morrowind or Oblivion player only), or Mod Organizer.
Join the Nexus to DL larger files. You can use NMM as a download manager and organizer, even if you don't use it to handle the game's state. Mods not DLed with it can be added into it.
S.T.E.P. is where you should start. It's a mod itself, and a vetted list of other quality mods, with a basic guide for their installation and use (you can use the wiki just for INI changes and a list of other mods, never using the STEP files, if you want, which is exactly how I started last time). STEP Core is basically all better aesthetics and interface, with either no gameplay changes, or extremely minor ones, all very lore-friendly. No need to delve into giant lists of random mods (instead, one giant list of very non-random mods). Then, to move on from that, check out GEMS (basically STEP for gameplay changing mods).
1K textures all-around, with 2K for clutter, NPCs, weapons, etc., works comfortably with 1GB VRAM. So, if your 570 is a typical 1280MB one, that will end up a major improvement over even Bethesda's hi-res DLC. You might be able to handle 2K across the board, but remember that this is Gamebryo, and you will get stuttering when you run out of VRAM.
ENBs look cool, but can be a nightmare to get and keep running, so don't jump in to that until you're ready, if at all. Forcing on SSAO in the control panel, and then doing INI tweaks for shadows (bigger shadow maps, and higher deferred blur mask), will take care of the most grievous visual problems of the stock game.
Gameplay-wise, Frostfall and Wearable Lanterns are both godly. If you are going to get any gameplay changing mods, start with them. One of the reasons to start down the road of gameplay changing mods, though, is that, being a wide audience multiplatform game (IE, kids with worn out controllers need to be able to beat it), even the highest difficulty can get really easy as you get higher in levels, with the vanilla game. So, play vanilla, but know that you can get mods to help keep large animals, bandit groups, dragons, etc. dangerous, as time goes on, should that be a problem.
If you want to play as an archer, definitely get some related gameplay mods, including a tweaked or disabled aimbot (INI tweaks). Stock archery is sad, as a seasoned PC FPS player. Since each has different characteristics, including compatibility with other mods, and that some larger-scale mods, like Perkus Maximus (formerly SkyRe) and Requiem, roll in beneficial archery changes, you'll have to navigate that yourself.
OP you can also use Steam Workshop for mods. I'm sure people will tell you that Nexus is so much better but I never had any problems with the workshop mods.
It's integrated with Steam, rather than being decoupled. It's easier to manage mods from multiple sources when they have to be gotten and updated manually, since updating a mod low in the mod order can cause problems. The Nexus has 95% of mods you'd want to use (unless you are visiting LL for more than the hair files currently missing from the Nexus...), so it is awesome, but in the end, they are 7z or rar files stored in a folder, and it's just nice to get as many as possible from one place.
Neither. Play it vanilla first. I never understood the fascination with substandard buggy additions bolted on to an even buggier GameBryo engine.
Not using them, of course you don't understand it. Most addons with any substantial amount of DLs and endorsements are far from substandard, and a good number make the game less buggy than as originally installed. The engine is still fairly fragile, but a merged or bashed patch is all that's needed, 99% of the time, when someone has major issues from mods. That, or they failed to read instructions.
TOTALLY new at this, can someone point me to the MODDING SKYRIM FOR DUMMIES thread...?
You'll have to read and follow directions, but a short version:
1/2. Get Skyrim to accept unofficial files (archiveinvalidation)
1/2. Get SKSE and SkyUI, because they are required by many mods. These go in the program folder.
3. Install unofficial mod files into Data. Loose files take precedence over ESPs/BSAs, should conlficts between the two kinds come up.
4. Some mods necessarily conflict with one another. Some come with patches for notable other mods, or have them available. For many, you'll need to use Wrye Bash or TES5Edit to make a patch for your specific set. This will be a non-issue or very minor one, for the duration that you are going for vanilla gameplay, though.
Mod Organizer keeps your program folder clean, but only by things not working will you find what mods get broken by that, sometimes. I find it more trouble than it's worth, since some mods don't play nice with the directory virtualization tricks, and it only takes a few minutes to back up the whole game + mods, but I get the appeal.
Nexus Mod Manager is a neat but buggy mod manager tool, that works much like FOMM did, with the ability to install and uninstall mods from a GUI. So, you register the mod (automatically done if downloaded via NMM, otherwise you have to browse to the file), then enabling it installs it, including making copies of files the mod may replace. So, disabling it puts those files back. Nice. But, it likes to crash, a lot, and when they come out with a new point version (like .4x->.5x), the new one likes to not see the old one's list. They excuse it being in beta, but that's just shit design, and it should be built to make sure that does not happen, or that it can be recovered from. If you use more than maybe 20 mods, NMM is best used as a download manager and mod sorter, not a mod manager for the game. Not existing outside the Nexus, and being many-game, rather than per-game, move it from being a good tool to a risky one, IME.
Wrye Bash is kind of old, and feels it, but it's got a history, and dammit,
it works. It can be used portably, so it can sit in your Skyrim folder structure, and you can back up
everything by copying the program directory and the My games subdirectory. But, it has a bit more of a learning curve than the other two, and many mods with options will need manual extraction of options, where basically all of those have NMM GUI installers.
For mods that cause CTDs when together, but aren't really conflicting in any meaningful way (like different item stats for the same thing in same location, etc.), using TES5Edit to make a merged patch usually fixes things, but so should a bashed patch.