Adobe allows you to download a full version of most of its programs for a free 30-day trial, including Photoshop Elements 2021. Here is that link:

https://www.adobe.com/products/photoshop-elements/download-trial/try.html

This lesson has a short video on what the download looks like - you just follow the steps!

Once the Photoshop Elements program has downloaded, you will probably see a shortcut icon on your desktop that looks like this:

You should be able to click on that shortcut and open your program.