Apologies if anyone has already brought this up, but for any tarp, paracord is your best friend…
Add lengths of paracord to replace the cord at each corner, looped at the end and long enough to be tensioned when erect.
Peg out one corner and hook the paracord under it, then walk 5-6 paces and put in the second peg (you get the idea…) until all 4 corner pegs are in the ground with a cord attached. The tarp is now flat on the ground and centred, ready for the poles to go up underneath it and stretch the cords.
If that takes more than 5mins then you probably spent time looking for a peg or a pole section… Hope that helps someone.