HoMM3 HD is a mod (add-on) for the game Heroes of Might and Magic 3.

In this post /post/541992/ and two adjacent ones, they were discussing exactly that – when I was figuring out the templates. The TE editor program is very convenient; it shows all possible map options for each template, although it doesn't seem to show the number of players or the possible difficulty level. You can also find the same information in rmg.txt – size (post above), then some column – number of players, but I couldn’t find where the game difficulty and other settings are located; you have to set them by trial and error. There is a lot of information about templates here /topic/6313/, but I still didn't find answers to some questions there.