Its complicated. I just took the poles out of a tent I already had. Though I did order some on Amazon, and they are actually much sturdier than the ones I already had. They are a bit too long though, so you'll need to take out a pole or two to make them work. I'll find the link in a minute.

EDIT: Stansport Pole Set for Rainer 3 Season Dome Tent https://www.amazon.com/dp/B00E8TJLGS/ref=cm_sw_r_cp_awd_WiqMwbFP605J5