Can someone give me the betting rules in limit holdem

can someone give me the betting rules for limit holdem.

if its 20-40

on the first 2 rounds it can only call 20??

wtf

Pretty much every single Limit game doubles the limits on the later betting rounds.

Its whats given rise to getting things like free cards from your betting by raising on the flop when its half the price of a bet on the turn.