Called, is a regular verb, the infinitive is "Call" and the mean (i'm going to show you with examples) i very common to use call or called (for actions in the past) when you use the phone or cellphone - i called my mom this morning with my cellphone. (the action is to "talk" with somebody) Also you can use called or call when you refer to names or nicknames: - my friends call me Jones. - my frineds called me with the nickname "Chubaka"

Ok, would is for a invitation, or hypothetical situations (wishes) for example: -Would you like to drink a coffee? -I would be better student. "Used to", is for habits in the past (something that you did in the past and now you don't do it) -I used to play in the park, when i was a child. -Do you used to play the guitar?