These form the fundamental building blocks to all the items you can use. Every item can combine with every other item, meaning that the basic combine into all other items. It's a little overwhelming choosing between those items at first, but if you understand the fundamentals it makes it easier. You can also use this cheat sheet to help you until you’ve got it all down. Most of the time when selecting an item on the carousel, it will be a basic item. Being patient when combining your items so you get the best combos, and actively searching for basic components during the carousel is key, so learn how to prioritize them.
When valuing combined items, it’s important to understand opportunity cost and how that affects the items available to you. If two items use the same component and one is more useful, it makes the second more situational and devalues it. Carries with three items are the major source of wins, so prioritizing what items you want for what champs you have and vice versa is critical. Be sure to plan ahead and get your best items on these carries that you’re building your team composition around.