I thought Schmuel was going as a logistics guy. It's actually a lot of the work, gathering up weapons, ammo, supplies. Also, and Jews did a lot of this, organizing small scale production. The Warsaw Jewish community tended to run a lot of small shops and family owned/run concerns that cranked out small stuff. As it happens, when they get stuffed in the Ghetto, they'll leave a lot of tools behind that are useful for this purpose.

There is at least one AK-affiliated Jewish group called the ZZW (Jewish Military Union) which is composed initially of Polish-Jewish ex-officers and later, various right wing aligned Polish Jews that exists from the invasion on, so there's options with that. (The ZOB, the Jewish Fighting Organization, is more labour-Zionist in nature and youth-driven. It springs up later)

I figure that the nature of covert manufacture of explosives and munitions means that it'll have to be done in small batches gathered over time. Food also, canned, jarred and otherwise preserved. That is more innocent as root cellars are a thing with Poles.