Scratch

Simple question but this topic is just for that, I will explain it as well as I can:

Step1: Open the project you wish to upload.
Step2: Push the share button.
Step3: A window will open up. Fill out everything on it, your password, username, the notes you want to appear next to the project tags, etc.
Step4: Push the okay button then wait until it says your project is online.
Step5: Click the link it provides, go to your mystuff page and your project will be there.