Re: She wants to start... but it's a no go :( help!
It's a poor man's truing stand. Find a front fork, mount it in a vice, put your rear wheel in it, you may have to force the fork legs out a bit to accommodate a rear wheel. Put a zip tie around the fork leg like I have in the picture so it just touches the sprocket, as you spin the wheel you'll be able to tell if there is any wobble to the sprocket. The zip tie "feeler" will help you see where the sprocket is either too far in or too far out and you can adjust the bolts on the sprocket mount until the zip tie touches the sprocket evenly all the way around.
Having your sprocket mounted completely straight and true is the single most important and most difficult part of installing a motor kit.