Yeah pretty much what scoob8000 said (at least for the basics). I use it all the time. It is in fact my preferred editor of choice now for text documents.
There are tons of shortcuts for searching/find-replace, etc. All of which are more advanced, but very easy once you understand it more.
Essentially you need to think of the editor as having 2 modes, a command mode (which is the mode it is in when you first open a file), and "insert mode" which is the mode where you can actually insert/edit data. The ESC key will exit from "insert mode" and bring you back to "command mode".
There are actually multiple keys that will take you from "command mode" into "insert mode", all of them have their own uses. For instance, the "a" key stands for "append" so it will place you in insert mode at the "right side" of the cursor. The "i" key stands for insert, so it will put you into "insert mode" at the "left side" of the cursor (think of it like inserting a bunch of characters before your cursor, or appending characters behind your cursor). Then there is "I" (capital "i"), which will start the "insert" at the beginning of the line your cursor is on. And there is the "A" (capital "a"), which will let you append data to the end of the line. Finally there is the "o", which will create a new line below the current one you are on and put you in insert mode.
The above combination of things makes it very quick and easy to make changes to files without needing to move a mouse/cursor around all over the place. You can replace a character by hitting "r" and then type the character you want it to be. You can also repeat the previous command by hitting the "." (period) key. This is very useful when you want to change say add a tab at the beginning of a bunch of lines to indent them (or comment out the line by adding a "#" at the beginning). Simply make your change once (from command mode: "I<TAB><ESC>", then move your cursor to the next line with the down arrow, and then hit "." and it will add the tab to the beginning of that line as well).
Copy/cut/paste uses the "yy" (yank line), "dd" (delete line, but more appropriately cut line (it serves as both)), and "p" (paste below), or "P" (paste above) (think of them like the difference between "a" and "i"). You can perform the action against multiple lines by typing a number before the command. Say cut 10 lines is "10dd". Please note these are all done from "command mode".
The ":" will do other things as well as save and quit. If you type ":1" it will move the cursor to the first line in the file. Substitute the "1" for any line number you want to use.
You can search for a string from command mode by typing "/" followed by whatever you are searching for and hit enter. Once you have searched the first time you can hit the "n" key for the next match, or the "N" for the previous match.