"Low level" is rather vague, but 1st level warriors are easy enough. Just create a Gnome NPC with levels in the Warrior class. For attributes, you use the following array: 13, 12, 11, 10, 9, and 8. Other than that, the process is very similar to building PC's.
Here's a 1st level example:
Gnome Militiaman CR 1/3
XP 135
Gnome Warrior 1
TN Small Humanoid (Gnome)
Init +1; Senses Low-light vision, Perception +3
AC 15, touch 12, flat-footed 13 (+3 armor, +1 dex, +1 size)
HP 8 (1d10+3)
Fort +3, Ref +1, Will 0
Speed 20 ft
Melee Longsword +2 (1d6/19-20)
Ranged Heavy Crossbow +3 (1d8/19-20)
Spell-like Abilities (CL 1st)
1/day - Dancing Lights, Ghost Sound, Prestidigitation, Speak with Animals
Str 11, Dex 12, Con 12, Int 8, Wis 11, Cha 11
Base Atk +1; CMB 0; CMD 11
Feats Rapid Reload (Heavy Crossbow)
Skills +3 perception ; racial modifiers +2 perception
Languages Common, Gnome, Sylvan
Equipment Studded Leather Armor, Heavy Crossbow, Longsword, Arrows x20