dmc_startbutton - First vote button in vote menu. [ Min = 1 | Max = 8] (Default: 1) - What is this?
dmc_langmode - Plugin lang mode. [0 = Server | 1 = Client] (Default: 0) - what is the difference between server and client?
Where I can choose what maps to load for vote? In map cycle? Thanks!
The button you press to vote for the first map in the list during a vote. (I'm inferring this from its description)
Either it uses the language configured for the server or the language configured by the client (client = player).