If you want to spawn an uber, you would do this:
#spawn sloth NameYouChoose 0 1
That will spawn a level 1 uber with no items, on team 1 (enemy). Team 0 is Citizen.
If you want to set a loadout, you would type this:
#loadout nameofloadout EXP 515000 claymore 1 dragonshield 1
Then, to make your uber spawn with that loadout, you would type this:
#spawn sloth NameYouChoose nameofloadout 1
That would spawn an uber at level 101 (based on the PCRPG exp system), with a claymore and a dragonshield. You have to manually put on the dragon shield for him (or any other armor, for that matter) since the bots won't equip them automatically. He WILL pull out the claymore, however.
The X Y Z options are just the coordinates for where you want the bot to spawn.. if you don't specify any coordinates, it will spawn the bot where you are pointing your crosshair.