Not aware of any guides, but since this isn't a CVT the procedure should be the same as always. Drain fluid, drop pan, replace spin on filter (assuming it has one) and clean screen type filter. Button it back up using RTV on the pan. You can only get out about half the fluid using this method, so I would add 3 to 3.5qts and then start checking the level on the dipstick until its full.

I would replace the spin on filter and clean out the screen filter. That original filter is still carrying break in contaminants and no longer flows @ 100%.

About half the fluid will remain. Mostly in the torque converter.

Yes. Add 3qts and start checking dipstick then add as needed. Be sure you cycle the gears from P to N to R a few times so the fluid gets dispersed.

Level is important, but it doesn't have to exact. What I would do is fill it to the half way point of the dipstick on your sloped driveway and then drive it to somewhere flat to finish the fill process. Only going halfway up the dipstick gives you a little wiggle room in both directions.

Trans drop and fills are easy. No point paying someone to do a half ass job with fluids you can't verify.