Oh yes great question.
I usually start by adding the roll and pitch basic gains to the x3 (or x2) channel. I use the same tx and find the sliders on the back work good because you don't need to take your fingers off the sticks to adjust. Start with those two gains and then slowly up the gains until you get oscillation then bring it back down until it goes away. Note, make sure your channel is going the right direction by verifying what direction the gains move in the assistant software.
After you feel a stable hover give it some hard inputs (within control/ ability/ safety) and see if you get any oscillation. Once you feel it dialed in, land and hook back up to the assistant software and see what your basic gains are at. You can unassigned x3. I personally leave the basic roll/ pitch gains on a slider because I like to be able to dial it in for different weather, wind or payload. Once I do the first set up, I'll disengage the channel, set the slider on the control to half way and then re assign the channel so the sweet spot is center position on the slider.
You can also go on to adjust the other basic gains in this same method, but vertical and yaw will not oscillate on a multirotor, so finding the sweet spot is a little more feeling out what works for your style. Atti gains simply act to dull your stick input which is more about personal feel for controls then aircraft stability.
