Miss Reid has very kindly created a video showing you how to access Google Classroom on an iPad. We hope this helps.
Please note that at present, only children in Primaries 5-7 have access to a Google Classroom.
The link for the video is below –
https://drive.google.com/open?id=1aWsoG8TvrfphlvsoL2MsHoOdiniU7nIA