Is there any good tutorial for messy uv1?

Hi. You do not need to edit uv_1 at all if you transfer them correctly from a similar item.

- find a maxis item of the same length as yours, clone, export, append in the scene with your garment, join if needed, rename to Reference;
- if your garment already contains body parts, select them and separate with P - Selection;
- if working in blender 2.7x, make sure both the reference and your item are visible and selectable;
- select your item, add Data transfer modifier;
- choose Reference as Source;
- enable Face corner data;
- enable UVs;
- change Mapping to Nearest face interpolated;
- choose uv_1 in the drop down;
- if you havent created uv_1 yourself, click on Generate data layers to create it;
- apply this modifier