Working from memory here but it's pretty simple.
1)Pull back and lock slide
2)Activate mag release and remove magazine
3)Push Barrel retainer button on front of frame and lift off barrel
4)Whle holding slide activate slide releas lver ( right side of gun) and slide it forward off the frame .
5)Finally it's a good idea to put your thumb/hand down o top of the hammer/frame and pull the triger to allow the hammer to come up (slowly) to take tension off it and prevent acidental release.
This is as far as you should have to go for a good cleaning and lube.
Assembly. 1)push back hamer2) install mag, 3)install slide and lock to rear,4) Install barrel.
My HS Mil sufered from missfires and jamming. It had been dry fired extensively ( by previous owners) resulting in a peened fireing pin. ( DO NOT DRY FIRE THIS GUN!) The fireing pin had to be replaced. That made the problem MOSTLY dissapear. Latter a cracked hammer pivot pin was found / replaced and it worked fine.
www.brownells.com has most of the parts for your gun.
hth
I like 30-50 wt synthetic oil on the slide but almost anything will work.
