I was asking myself the same question and the two answers you got are really off the mark, so I thought about it and I'd like feedback to see if there's any holes in my views, note that I have no combat training whatsoever and no experience past street fights with the police during riots and protests where we used comprehensive tactics such as black bloc, buddy system, with intelligence, medical and legal teams as support etc. (we should do a thread about that someday)
European countries have for the most part gun control laws and no conscription so people are untrained and are unable to access weapons. What revolutionaries who want to fight should prepare for is the moment when mass movements will potentially devolve into armed conflicts and civil wars. At this point weapons will become accessible trough the looting of military and police stockpiles.
So the thing to do meanwhile is to prepare for things that do not necessitate weapons, fitness, combat medic training, theory of small unit tactics, basic survivalism, how to do urban warfare, how to function in cells, OPSEC, INFOSEC, stockpiling supplies, drugs etc etc.
For actual and physical training with firearms, there is travel, it can be expensive, it necessitates contacts, it can be flagged but it's one of the ways. Say you know people in the US who happen to know about guns and you travel there for vacations for example. I don't know how useful it can be to train in small teams with airsoft/wooden guns but I think it still can be useful because I saw that some armed forces with supplies issues trained their soldiers with mock ups.
Note that groups like "action directe" and "rote armee fraktion" operated in Europe for a long time and didn't have extensive military education, even though RAF people traveled to Palestine to get some firearm training. Although I think this kind of vanguardist - some would say adventurist - strategy they did is quite sterile because it lacked mass support, it's interesting to look at how they formed and operated to know what's possible to do with the right tactics, even though state security services came a long way since then.
To conclude I'd like to say that I think it's quite useless to look at how party based revolutionaries operated decades ago in other continents and hoping for something similar because big communist parties in Post too long. Click here to view the full text.