Is the computer connected via WiFi? or Ethernet?
Do you have any other computers or devices that can print wirelessly?
OK are you sure the printer is connected to your WiFi Network?
OK I can connect by remote and see what is happening.
If you want me to do that please Accept the remote assistance offer. Plug the printer in by USB and install this firmware update before we begin: https://www.usa.canon.com/internet/portal/us/home/support/details/printers/inkjet-multifunction/mg-series-inkjet/mg3520?tab=drivers#Z7_MQH8HIC0L88RB0AMD0F1Q42K25
Select Firmware then select the Windows version
Printer Firmware Updater (Windows) for MG3500 series Ver.1.0
Did you do that?