Clothing templates in roblox studio or platform with BC?

Okay so basically I wanna make my own clothes for my mmorpg game and all I have to do now is upload it to my profile. The problem is it asks that I need builders club to make a shirt when I don't wanna upload the shirt to the whole platform I just want it in my game and im thinking do I need a code? where can I get a code for my shirt without actually uploading it?

You can upload the templates as decals and set the ShirtTemplate or PantsTemplate property to the content ID of the image.