I am having trouble putting my bike on its centerstand

Put bike on sidestand
Stand to left of bike
Put left hand on left hand grip
Put right hand on handhold. Handhold is either the metal bar by the passenger peg/helmet lock (my choice), or the grab bar (Bend at the knees, not with your back!)
Push down on centrestand footpad until one of its "feet" touch down
Push the bike away from yourself until the the other centrestand "foot" touches down
Push down on the centrestand footpad with all your weight, and pull back and up (mostly back) with your right hand; it may help lean your right knee into the side of the bike
The bike should pop right up