Depending on your affiliated Infantry Battle School you attend (also making the same assumption you're Infantry based on your use of the acronym "BIQ" - the Career Manager of your Corps has the knowledge of which Battalion of your affiliated Unit needs a new soldier the most.
Most of the time they DO try and place you regionally specifica to where you want to be - either based on your current family situation, next of kin and the like.... just be ready for the shocker should you get the total oposite side of the country that you were hoping for!!
It happens I think to every soldier at one point in their career... If you're just entering the Regs, all I can offer you is to (a) pick the closest affiliated unit to wherever in the country you'd like to be in, (b) have an acceptable alternate ready in your head, (c) accept whatever posting with open arms, as the new fish in the pool you have less of an oportunity to barter for position, and (d) whatever comes - enjoy your new career, learn to be a part of the team, adopt the "eyes open - mouth shut" approach for a bit until you got the hang of the new place and be safe in all your endeavours...... if you can't be safe - drop the hammer on the bad-guy first!!
Cheers