If you have some local files that you would like to upload to an existing repository in DCS, you can follow this process. Note: if you are uploading lots of files it would be better to use a git client, this workflow is ideal for one or only a few files.
On the main page of a repository, near the top and in the middle of the page there is button labeled Upload File, like you see here:
After clicking Upload File you should see a page that looks like the following screenshot:
You can either drag and drop the file from your local system or you can click anywhere in open space surrounded by the dotted blue line to open a file browser.
One you’ve selected the file you’ll need to select Commit Changes at the bottom to save them to the project.