Importing from Github is easy, but requires some unusual steps.
Start the web browser
If you like, you can use Safari to browse the web. But the most efficient workflow is to use the built in browser. In document library tap on the + icon.
Please choose Github which starts the internal Copper web browser and point it to the corresponding homepage which saves you some typing if you typically download files from these services.
Downloading a ZIP file from Github
Github offers a service to download the whole repository as a ZIP file, which is what we need. But this option is not shown in mobile skin.
First, search or navigate to the repository you want to (partly) import into Copper for iOS. Then, scroll to the bottom of the main repository webpage (i.e. https://github.com/pichenettes/eurorack/).
At the bottom of this page, tap on the "Desktop version" link. This will reload the page, this time with Desktop skin, which is a bit harder to navigate on the small screen. At the top of the page you see that green "Clone or Download" button. Tap on it and then tap on "Download ZIP".
Copper will catch the downloaded ZIP file and handle it. If the repository you downloaded contains .brd or .sch files, Copper will immediately start downloading the file and will bring you back to the library. If you selected to download a .brd file, Copper will search for a .sch file at the same location, as EAGLE files mostly come in pairs of a layout and schematics file.
If you download a ZIP file, Copper will download that file and examine its content. You will then be presented with a screen that let's you choose which files Copper found in the ZIP should be imported.
Once you have made your selection you are brought back to the library screen where the new files should be presented. It might take a few seconds until the thumbnail image is rendered.