This is really pretty easy:
- Click this link to install Teamviewer 12: https://download.teamviewer.com/download/TeamViewer_Setup_en.exe
- Instruct the person you wish to help to download and install this link: https://download.teamviewer.com/download/TeamViewerQS_en.exe
- Have them run TeamViewerQS and they will have a meeting number and a password to give you
- You run your local copy of TeamViewer and in the Remote Control section, enter the number they give you. – You will then have a box to enter their password – soon, their desktop will appear on yours and you can start controlling their PC – this even works for rebooting.