OpenShot (Windows, Mac, or Linux)
Can be downloaded from: https://www.openshot.org/download/
make sure you don't click on the fake download buttons (misleading ads), but instead the blue button (actual download link)
choose the version that is compatible with your computer
Paint.net (Windows only)
https://www.dotpdn.com/downloads/pdn.html
make sure you don't click on the fake download buttons (misleading ads), but instead actual download link
You'll need to download the .zip file
Go to your downloads folder, then select the .zip file you downloaded
right-click "Extract All" to get the installer.
double-click on the .exe file that has been extracted to begin the install
Pivot Animator
please see the Pivot Animator page for the link to the program
SketchUp
please see the SketchUp Tips and Tricks page for the link to the program and the web version