spear is a one hand oberated weapon that lets you strike with one extra rank however they can only make one attack.
shields gives a 6+ armour save that can go with other armour also if you have a hand weapon you get a 6+ ward save in close combat.
hand weapons can be axes swords or otherwise, but does not give any bonusses and are carried in one hand
a saurus has 2 arms (normally) and can carry a spear in one and a shield in the other, has a total save of 4+, and can attack in 3 ranks. the ranks after the first only attack once this is called supporting attacks (4 if in horde formation).
however it is a better option (thinks most people on this forum) to keep the hand weapons as you dont have to buy spears and get a 6+ ward save in close combat and can attack in 2 ranks.
try reading the big book it really helps......