I'm a AE newbi. Can someone please explain the AE bid preference blocks?

Sel -- Nbr -- Base -- Eqp -- Pos -- Low Nbr -- Low% -- Reg Only -- Tr Bv

I get Sel, Nbr, Base, Eqp, Pos; but I do not understand Low Number, Low %, Reg Only, and Tr Bv.

Can someone please give a good run down on these and how you would use them and the syntax required?

Thanks ...

-Fatty