I have an older iPad Air. Said it hadn’t been backed up in 10 weeks. So I plugged it in and did update. The main screen came on but when I went to an app it flicked right back to Main page.so I shut it down to restart. Now

I have an iPad Air 5. Said it hadn’t been backed up for 10 weeks. So I plugged it in and did the update. When it finished the main screen appeared but when I went to any app it flicked back to main page. So I decided to shut it down and restart. Now it is frozen on the apple in center screen and will not go anywhere. What should I do? I have a newer iPad and wanted this one for the grandkids.