Firstly go to https://rustdesk.com
You should see a page like this below. Click on the Download App button.
It would redirect you to github page. Click on Windows to start the download.
Download will commence
When it's done, click on the download icon from the browser and click the file to open
Then you'll get a screen like the following. It will display your ID. This is the ID that you can give to the Customer Service Representative so they'll be able to remote desktop to your computer.