31's would normally fit a later Ranger, but I believe the Explorer is a little tighter fit. I have trouble finding stuff here too.
Anyway, basically you take starting measurments on your height. And assuming no one has lifted it before, you dont want to go more than 2" above where you start. And you might put some lube/wd40 on the threads to soak a while.
Lift the front off the ground by the frame, leaving the front suspension to relax, this allows the adjusting bolts to turn eaiser and not be as likely to strip the threads and such. Counting the number of turns, crank them in some then let the truck down. Drive it around the block and measure how much it raised. Repeat as necessary. If too much, simply back off the bolts some.
Now get a front end alignment.
Maybe someone else can point you or add something I missed.