I would question whether a manual can be taught in a day.
I’d suggest your better trying to crack wheelies first, then move onto coaster wheelies (not pedalling but sitting down wheelies) then think about manuals.
If you can coaster wheelie you’ve, in concept, got a manual covered, other than the method of starting a manual versus a wheelie.
The manual starts without any pull on the bars, moving your weight backwards with straight arms and bent knees and pushing through your feet, then keep it going all through the knees pushing and absorbing the momentum while covering/dragging the back brake for fine control.
I think coaster wheelies, sitting down, while going down hill using the brake for control are the way to start and learn the knack of manuals. Good luck. Takes years of practice rather than 1 day of learning – IMHO.