Import Units and mastefiles

[crocodile27]

Hello everybody I own this lovely game, the gold edition, but couldn't relly enjoy it fully cos I don't understand many things about the random games that is the main reason I bought this game, and the editor. I read some of the documentation but I'm very new to editing and can't understand. I just need to know 2 things can you point me straight in that direction?
1) I would like to import units made by some scenario author in random games. ex I found biplane triplanes in a scenario around WW1 and would like to import them in a random generated game that feel for instance "WW1". And then to lock further research so that the other AI Regimes don't research further than the technology that was used during that period. So in a similar way I would like also to start a gme in the 90s so with all the regimes at a certain level of technology let's say III and above, with nuclear research already known... How should I do that?
2) I don't understand what Masterfiles are about.... what is the difference beetween the one with AT2 as suffix and the one with .masterfile as suffix? Which one should I select when I create a random game?
Thanks if you can help me in these 2 aspects , but they are very important to me and everything about editing and importing it's very very confusing for me. Many many thanks in advance if you can help.

[Twotribes]

I don't know the answer to your questions, but am surprised no one else does either.

[crocodile27]

I actually found a way to answer myself since nobody was able to help or had the time to do so, but it took many hours, and still don't understand whats the difference with the at2 and .masterfile suffix, and also why in the random game I edited, importing units from other scenarios and changing rulevar to forbid research the cities start with some production already set and why not empty. Surely I would welcome a guide where rulevar are better explained and also where to look for to understand how the AI chooses what units to produce...

[Twotribes]

Open the editor and look around. Pretty sure the instructions for AI production is there. I am not very good at editing I did know sort of what I was doing a couple years ago but have forgotten it all from lack of doing it.