It's fairly easy to find instructions on how to make guns, bombs etc online. For example, if you search for "improvised munitions", you will find many copies of this floating around:
Or for something more oldschool, search for "expedient homemade firearms". I got my paperback a few years ago from Amazon, as well (sadly gone now, but some derivative works are still around if you look).
https://en.wikipedia.org/wiki/TM_31-210_Improvised_Munitions...
And if you wanted that on paper - or on your Kindle - Amazon is happy to oblige:
https://www.amazon.com/Improvised-Munitions-Handbook-TM-210/...
Similarly, for homemade guns, there's e.g. FOSSCAD (and there are many forks of that repo on GitHub even):
https://fosscad.org/
Or for something more oldschool, search for "expedient homemade firearms". I got my paperback a few years ago from Amazon, as well (sadly gone now, but some derivative works are still around if you look).