New to wargames and would appreciate some advice.

I've been playing a lot of shadespire, underworlds, Warhammer kills teams etc short skirmish type games and would like to try a larger scale wargame and was looking at 15mm or 10mm miniatures, but I feel quite out of my depth. I'm not sure on how basing works for these smaller models and the ruleset i was recommended was DBA or laming? which id never heard of before so i did some research and i dont really understand xd

are there "set games" like the skirmishes I'm used to in this format? or do you pick a rules set and play with that?

sorry if these are dumb questions, the only tabletop game I really know is Warhammer which is very accessible and commercialised.

Thanks in advance!