Google your question and you should find the answer there. I just did and saw that there is a relevant youtube video. BTW, I teach imaging and I hate the way Universities, schools and others all believe the world revolves around Adobe. I teach GIMP and darktable mainly to my students. Fewer and fewer people are wanting to learn Photoshop and lightroom. I suspect the subscription model drives many people away.
I believe Adobe Bridge can make contact sheets and a little known fact is that Adobe Bridge can be legitimately downloaded free of charge (at least was the case when I last looked).
That is true, but I believe Bridge has been discontinued for a while already, at least its original, for the lack of a better word, form. I have not checked if they restored its functionality.
Thank you for your reply.
I’m on GNU/Linux and use only free software, the course I’m taking uses adobes software.
Even if you can download an official version of Adobe Bridge for free, I don’t want it.
I do the course work with adobe on the school’s computers, but I’d like to develop my skills only with free software.
Then give gThumb a try, under Tools you’ll find the option Contact sheet, select your photos and there you go. Numerous ways to alter the appearance, default is this: