The bomb is the smoke bomb. It lets you leave the fight immediately and works on almost all foes.
The light sources are a torch, an amulet that the Lizard priestress gives your PC (not available if the witch helped with her light source) and an armor but it's only available way later than the other two.
To make a torch your PC needs to build the toolroom / workbench or so. I can't remember what it's called but it will be obvious when you check the screen that shows you what you can build to improve the teachers hut. To get there you need to click the tool icon in the main screen when your PC is in the hut. It has a hammer and another tool in it - there will be an area "Improvements" that shows you what can be built and what you need for building.