I've just refitted my centre stand, but managed it on my own.
Raise the back end of the bike so that the centre stand is off the ground by an inch or two - I used an axle stand under each axle nut.
Place the pins in the holes in the frame.
Fit the springs, so that the stand hangs from them, with the stand feet forward and down, the pivot holes rearward and up under the frame.
Line up the holes as close as you can get them, then on the right side press down on the stand foot with your right hand (keep your arm fairly straight and use your body weight). Line up the hole and press the pin in as far as it will go. It won't go all the way as the other hole isn't lined up.
Swap sides and hands (left stand foot with left hand), and push the pin home. Back to the right side again, and push the pin home.
I found it worked because I could use my weight to stretch the spring (no pulling/pushing).
I also tried it with the stand hanging under the frame, but with the feet rearwards. There are too many obstructions on the frame to line up the holes.