tdemasters

Hey everyone, I am new to the form and hoping for a little help. I have a 1974 Yamaha DT 250. This is my first bike rebuild and I am having trouble figuring out where the tubes off of the Carb. need to run to. As far as I can tell there are 4 openings, from reading other forms I have found that (aside from the gas inlet), 1 is a vent, 1 is an overflow, and 1 has to do with the oil mixture system. I don't know which is which. Sorry if this is a dumb question just looking for a picture of the carb fully set up and a little explanation as to what each thing is. Thanks in advance!