Double click the .ytd file or use right click and select "edit". In the texture editor, click on a texture to select it. Then, click the replace button and select the texture you want to replace it with.
If you have any more questions, please come to my Discord if you have the opportunity.
You are using the wrong version of the EUP. Next time, I ask you to read the entire description carefully and think about it, e.g. do you have the right staff. Somewhere above in the comments you have how to remove masks.