First download Inkscape 1.0.1 from their website. Inkscape is a free and open source vector graphics editor for Windows and OSX.
Download the jigsaw extension from GitHub. GitHub is a code repository familiar with coders, so the interface may look complicated, but all you need to do is click on the green 'Code' button and choose download zip file. The two files you are interested in are: jigsaw_puzzle.inx and jigsaw_puzzle.py
Drag jigsaw_puzzle.inx and jigsaw_puzzle.py into the extensions folder in Inkscape. These folders can be found by clicking on Edit -> Preferences -> System: User extensions in the Inkscape program, but for your convenience I have listed the pathways below:In Windows you can find the extensions folder in: C:\Users\yourUsername\AppData\Roaming\inkscape\extensionsIn OSX you can find the extensions folder in:/Applications/Inkscape.app/Contents/Resources/share/Inkscape/extensions
You will need to restart Inkscape once you have added the extensions. To run the jigsaw generator open up Inkscape, click on the extensions option in the menu bar, select Render and choose Jigsaw Puzzle Generator