“I usually just fast forward through the commercials.”

You are having a conversation with your friend about a TV commercial, but you haven't seen it because you don't watch commercials. You have a DVR and always skip commercials. You explain to your friend:

I usually just fast forward through the commercials.

just (do something)

You use this phrase when the action you're describing seems easy, simple, fast, or unimportant:

I just googled "new york florist" and that was the first shop that came up, so I called them.

fast forward through (something)

You "fast forward" a video or an audio recording in order to move to the next part more quickly. When you fast forward through a part of the video or song, you are skipping that part and not watching it.

the commercials

"Commercials" are TV advertisements. In the U.S., several commercials are shown in a block between segments of a TV show. "The commercials" refers to this period of time when commercials are being shown.