You make the best combination of your hole cards and the community cards. So if you have Ah Ad in your hole cards and the community cards are 10h 6d Ac Ks 2s, you’re hand is Ah Ad Ac Ks 10h.

An important note is that you do not have to use any of your hole cards. If the community cards are A K Q J 10 of Spades, then your hand is the same the community cards (along with everyone else). In this case you do not use your hole cards at all to make your hand.