The Air Defence capability, specifically ground to air shooting is pretty much non existent right now, so there is no training for that like there might have been back when we had air defence equipment. There is plenty of crossover still i.e. RADARs, UAVs, air space control etc., but you won't get that type training until you get a bit of time in. The more technically sound you are, the faster you could get there if that is what you want. There are many different routes, guns/CP/Recce, OPs (FOO/FAC), STA (UAV and RADARs), you could take after DP1, just continue to perform well at what you're tasked to do, and you'll figure out pretty easily where it is you want to be.
For your DP1 you will be likely trained on a gun (howitzer), maybe mortars. After training you could be posted anywhere, and I'm not sure which regiment needs new troops. Plenty of Francos have been posted to 1 and 2 RCHA. It seems your English is pretty good, and maybe you should take advantage and get youself fully bilingual (exempt) early on in your career. If you truly want to stay in your motherland, then make sure you put forward your best effort at all times, because at some point they may ask everyone where they want to be posted. Better performers will get priority.
Welcome to the GUNS!!