1) I'm not sure. I'd have to check the mod editor to figure that out. You could do the same in the same amount of time as me.
2) There seems to be a variable in the mod editor called "PARTY_MAX_LEVEL" or something like that which is set to 50 for all difficulties, but I got to level 61 in my game, so I don't think that variable is used, or at least isn't used for limiting the party's level. I guess you can get as high as is possible within the limitations of the type used for the level variable internally. If it's an unsigned 64-bit integer (total guess here; probably not right), the max level is 18446744073709551615. You could only get there with editing something unless you figured out a way to live forever and played Lords Of Xulima for the rest of your eternal life.

3) You need to open the mod file from where Steam saves Workshop items to, which is in C:\Users\[username]\Documents\Libraries\Steam\steamapps\workshop in Windows, I think. Use the mod editor which you can open with "Open the LoX mod editor" from the mod menu in the top-left corner of the main menu.

(I had to post this part in a separate comment because Steam Workshop comments are limited to only 1000 characters each, for whatever reason.)

Yes thats exactly it. May I ask you a few questions.
1) Which settings I have to adjust to have endless numbers of monsters?
2) What is the max level of the group?
3) How can I have a look at your settings (I do not know how to open eg your file?
Thank you very much for your answers in advance.

The reason I combined all these concepts is because only one mod is possible. Mods in this game are just sets of game variable values. What's "the grind mod"? If you describe it and I like what you're talking about, I'll add it. It sounds to me like it probably means endless monster packs, which I don't like. Is it something different?

Can you please add the grind mod as it is currently not possible to activate multiple mods for this game. Does anybody know how to activate two or three mods for this game.