Below are common issues and their solutions. If you run into something not listed here, leave a post and I'll do my best to answer!
My character parts are not aligned properly!
This tool is meant to use same-sized assets. If you have assets of different sizes, it will not work as intended.
My character is blurry!
What you see in the editor is only a preview, when you export your character they will be the size of your largest imported part.
My parts are in the wrong layer!
Click the incorrect layer and the asset window will focus on the corresponding parts, letting you correct the mistake.