I shift the bike into neutral, then as the others said,, lift on the rear grab handle.
It takes more effort to get it up on the center stand than other bikes I have owned.
It'll get easier to do once you get the hang of it.
Seriously consider the side stand relocation modification.
2012 KTM 690 R
2012 KTM 990R Adventure
2014 Triumph Explorer XC
"Walking thru life to an unknown destination and trying to enjoy the adventure getting there"