Stalling as soon as clutch lever is released.

As Melnic said try letting it warm up first and see what you get.
How's your oil level. What type did you use.
For the center stand right hand on the loop right foot on the center stand lift straight up and rock your body slightly right, should go up easy. Grease it and work it a bit while on the side stand, see if that helps.
Someone just recently posted a video on it, once you get the knack for it it's easy.
There was a thread on freeing stuck plates or sumpin'. In it was suggested to put the bike in neutral, engine off, clutch lever pullled in and kick cycle the motor. You may feel resistance on the first kick, mebbe the second too. About the third cycle there should be no resistance.
If for nothing else it's kinda fun to do........
Johndaddy was quicker

Not sure if it helps but getting it onto the Central stand
Standing on the left side
Left hand on left handle
Foot on the stand keep machine straight so both sides of the stand is on the ground.
Right hand grabbing somewhere middle of the saddle and down under on the frame or so
Then pull in about 60 --70 degrees 2 o'clock direction depending on your length
It can take some force but it is simpler once you find the right direction
Also there’s a little trick to using those center stands. Use the board as Paul suggested and try it this way.
Also, the centerstands on these have quite wide tube pivots. If they dry out (and get rusty), they bind up big time when you put a load on them, like when trying to put the bike up on the stand. Keep them well lubed and it will make an amazing difference. I go through the trouble of installing grease nipples on the pivots so I can do this ......

Still even needed my cousin who has 100 pounds on me pull it back while I held the centre stand down with my foot otherwise it just snaps back up.
It's all in the technique. Push the stand down to the floor, now stand on the tang... put all your weight on it (the tang) and at the same time lift straight up on the passenger grab bar. Never pull back... pull straight up. Yeah... it's harder than most, but you should be able to do it by yourself. Fwiw, I shortened my stand to make it easier, but at 5' 8" and 160lbs I was still able to do it before I shortened it.

Re the clutch: There's 6 springs built into the basket that are cush (cushion) springs. They act as snubbers. Not unheard of for 'em to break. Without them acting as a cushion, the clutch will be awful grabby and jerky. Might be worth having another look?
Do as Jim says. It is all about technique and having the confidence to hold the bike perfectly vertical. It feels very strange holding a bike perfectly vertical at first because the worry is it will topple over. The Virago XV1000 is the easiest I have owned to put on center stand, you just put all your weight on the stand's tang and up it pops. Incidentally the Yamaha Manual calls the center stand a work stand - there's a definite logic to this name...:hump:
My 83 XJ650 is easy to put on center stand, '78 XS650 is painful and I have to have my hard sole boots on to do it.
BMW is piece of cake and a heavier bike. Center stand is lubed , I think the balance is off on the '78 center stand or the stand is taller or something