Screenshots can be made at any time by pressing the Ctrl and F5 keys at the same time. This should be true for any game that uses DosBox. Screenshots will be found in the capture folder of your game. This folder may not be created till you take a screenshot for the first time.
Screenshots taken by this method are about a quarter of their proper size. This might be the fault of the settings used.

Greenshot is a freeware screenshot program, that is very versatile. Its screenshots are of the proper size.

In the days when Ishar 2 was created, screenshots used up a lot of memory, so it was simpler to use pen and paper. These days, screenshots use up very little of a PC's memory. Hence they are quicker, simpler and easier than taking notes with pen and paper. Also, no chance of making errors when drawing up the latest map.