Online timer

but i couldnt figure out how to make
it do something after the timer
reached 0.

You can check if the remaining countdown time is smaller than 0 and if so call the function/event that you want (and also clear the timer so that it stops executing)

I couldnt find how to make it ‘start’,
as in the world settings I can choose
the game mode and player pawn but i
had no idea how it worked with actors.
My actor was an actor blueprints
class.

Not quite sure what you mean. You can spawn actors via “SpawnActor” from blueprints during runtime and you can drag and drop them into the level from the editor.