If you would like your students to be able to log attendance through their member app, you can do it by going to:
Left Side Menu Bar > More Features > Member App
Under "Spark Member App" page, scroll down and select "Settings" tab.
On "Settings" page, select "Member App" section and click "Attendance".
Under "Attendance Settings" page, toggle ON the "Allow members to log attendance" option and make sure to click "Save" afterwards.
Once done, as long as you have the coordinates of your school and the students have location privileges on, they would be able to check in via Member App.