That is just for an overall kind of info. If you want to learn how to play a specific hero and what items you should be buying for it you'll need to find some guides
http://www.dotafire.com/ has lots of info and various player made guides for that.
You are better off just following the in-game "core" and "situational" lists. Getting any of these items will never be the reason you failed in a game, even if they aren't always the ideal purchase based on your level of farm, your lane and the enemy team composition. For quite a while there will be many many more reasons why you fail or lose other than your item choices, especially when it comes to farming (last hitting, stacking, ganking and taking towers).
There are very few heroes in DOTA that REQUIRE a certain build to be effective, and even then in the hands of a good player adjustments can be made to suit the team better overall.
Instead of reading build guides you will more quickly learn and get better if you take a little time and gain a grasp on all of the items, their cost and their buildup. Some games you will want a mkb, some you will want a bkb, learning to understand why and when to get either instinctively will take you so much further than looking at build guides, and make the game more enjoyable.
Again the in-game lists are fine with one extra consideration: the importance of team utility items like Drums and Mekansm. These can be bought by pretty much any hero and your team should see that someone gets them, support, semi-carry or even sometimes carry. You might very well deviate from your "list" to buy one of these items for your team.
Additionally, Pipe of Insight is great against a magic heavy team and urn of shadows is another team utility / healing item that helps when you want to sustain pushes.
Basically, if you have a grasp on the items, you shouldn't have trouble formulating a plan without a guide before too many games. If you take some basic things into consideration, and even occasionally experiment you will be a much better player and win more games than someone who just skills and buys what a league of legends player tells them to. Oops Freudian slip.