I put springs in absolute last. So, both lowers first, then uppers (if your kit came with them but I doubt it), then springs. Flex each side out to fit springs in. I've done multiple lifts this way with just simple hand tools and it works great. Also, with the springs not in, you have much more finesse over the front end without having to fight with the pressure from the springs.
91 YJ: 2.5L, 31 A/T's, Crager soft 8's: SOLD
94 ZJ 5spd: RE 3.5" Superflex Kit, HPD30, Lockright, 32 Maxxis Bighorns, Rhino-lined Floors, Homebrew Sliders, Hacked fenders: SOLD
98 ZJ: 5.2L, RC Budget Boost, 16" Moabs, Goodyear MTR's, NP242, Magnaflow 3"