User johannes told you how to do add existing files to a Git repository in a general situation. Because you talk about Bitbucket, I suggest you do the following:
Create a new repository on Bitbucket (you can see a Create button on the top of your profile page) and you will go to this page:
Fill in the form, click next and then you automatically go to this page:
Choose to add existing files and you go to this page:
You use those commands and you upload the existing files to Bitbucket. After that, the files are online.