Got a new iMac but the wireless trackpad and keyboard aren't working.

I’ve tried clicking the power buttons on the trackpad and keyboard. This causes the green light to show up, so they’re not out of batteries.

The trackpad and keyboard were working before when I was registering the computer, etc. But they stopped working after I migrated my old computer’s files onto the new one. So now I can’t get out of Migration Assistant.

I can’t call Apple Support because it’s closed, and I haven’t found the answer on the Google.

Any ideas?