We're saying the same thing but I'm adding the forward assist out of personal preference. The bolt release is a button on the middle of the left side of the receiver. It's purpose is to release the bolt so that it may strip a round and chamber it. The forward assist is a plunger that pushes the bolt fully closed. In the event there is fouling, debris, or other types of matter that keep the bolt from fully closing, it will usually happen when the first round is chambered. This is because the bolt travels less distance on closing and has less force when it's being released from the bolt release.
You don't have to smack the forward assist, but it's good practice to do this as a matter of course. It's really a good way of preventing a jam but does add a bit of time to the total sequence. Problem is, that once in 100 magazines when you should have done it will cost you your life. If you pull the trigger on a not-fully-closed bolt, you have to recharge the rifle with the charging handle. That procedure takes vital time. Seing as how you've already needed the rifle when you first pulled the trigger, you are now in trouble. Hope this helps.