@FediTips The channel boosts videos posted by the peertube account in that channel. So you’ll only see the videos posted to that channel from that account. If you follow both the account and the channel however, you will not really see the boosts because mastodon filters out the display of boosts of posts already in your timeline.
I just did a test on my own peertube server to confirm, and I only followed a channel. When posting to that channel, the video showed up in my mastodon timeline as a boost from that channel.