for a start

In the first place; to begin with; as the first of a given set of points (e.g., in an argument). You're bored and don't know what to do? Well, you could go play outside, for a start! I'm sick of living in this city—for a start, the traffic makes commuting to work an absolute nightmare! A: "OK, what did I do wrong?" B: "Well, for a start, you put all of yesterday's paperwork in the wrong file."

for a ˈstart

to ˈstart with

(also for ˈstarters informal) used for giving the first of several things or reasons: You’re not going to marry him. For a start, you’re too young. For another thing, you hardly know him. ♢ She wasn’t keen on the idea to start with.