Try not to be too disappointed that a keyboard player is giving a bass tutorial. :)
Also, one thing I did not say in the video. When catching the rhythm on the "and" of 3, it is best to mute the string on 3 and then grab the "and" of three.
When working with singers, we'll often tell them to breathe on the beat before their entrance to help nail the timing. Muting the string on the bass before playing is like breathing. It will help nail the upbeat.
If this "and" of 3 stuff is confusing, it will make more sense after watching the video.