These support pages outline the available methods to restore an iPad - either from a backup, or to Factory Settings:
Restore your iPhone, iPad or iPod touch from a backup – Apple Support
Restore your iPhone, iPad or iPod to factory settings – Apple Support
Restore all content to iPad from a backup - Apple Support
You’ll need access to either a PC (with iTunes installed) or a Mac (with iTunes or Finder - as appropriate for the installed version of MacOS).
Download and use iTunes for Windows – Apple Support
Update to the latest version of iTunes – Apple Support
If your iPad is not detected by your computer when connected, try using a different USB port. Otherwise, this support page may help with troubleshooting:
If your computer doesn't recognize your iPhone or iPad - Apple Support
Use of a PC or Mac computer is unavoidable. If you don’t have access to a suitable computer of your own, that of a helpful friend or family member will suffice. Alternatively, the technicians at the Genius Bar of your local Apple Store or Apple Authorised Service Provider (AASP) will be delighted to assist.