To start, check out these handy templates which ROBLOX themselves has created. If you right click and save these images, you can use them as a guide on how the clothes should look once you upload ...

Roblox is an online gaming platform and a tool for game development created by the Roblox Corporation. It enables users to create games and play those that are made by others.

Clicking on the "Get More" button at the top right lets you obtain even more customization goods for your character with your Robox.