Sorry mate, but all Army personnel are soldiers first, tradesmen second.
You will attend Phase 1 training which will teach you all about soldiering, then Phase 2 will teach you all about policing within the mob. It's the same as the RAF Police and RN Police.
You will not be a police officer though. You will have now powers over civvies unless they are dependants or contracters overseas.
If you want to be a real copper working with servicemen then join the MOD Police.
Try www.arrse.co.uk for more info