I received this question via support and wanted to share more widely:
1- If I input students in my course using the roster tool, do I still need to share individual assignment links with them for each assignment?
Yes–you can post these to your syllabus or your LMS. GitHub Classroom does not email students.
2- Do I have to share the link to each assignment or are the students added to my classroom and can see subsequent assignments after I provide them with the first link?
You’ll need to share each Assignment link, but this is a great feature idea–mind opening an issue?
3- What instructions should I give students to be able to submit solutions using classroom
If it’s solo work, you can have them commit directly to their master branch, and then you can click into each individual commit to give feedback in-line. From there, students can post the link to their repository to your LMS.
You may also want to see the workflow suggested here: How to grade assignments on GitHub