If link is going to Gist.Github, then visit it, click on Raw button and copy code
Then, simply paste it in your editor. In some cases, if you see code instead of blocks, you need to switch to code view (top right 3dots and select to use code view), paste code in code view and switch back to visual view.
If link is going to library, then you can import and find this element in Experimental/Fancy section of library
There are many ways to make infinite movement in Greenshift. But simplest way is to use CSS transformation panel.
And setup is easy. Add init and infinite styles