Current serving Techie here, how the fresh blood has been brought through has changed a lot during my time and it seems it's going to change again if the recent brief we received from the TG1 Sponsor bears relation to actual future events....but it boils down to.....
Basically, once you've graduated Halton and Cosford you'll be an AMM (Aircraft Maintenance Mech) posted to a 1st line Sqn. What does this entail?
You will be responsible (Post local training) for the safe receipt / dispatch (Think a set of events using hand signals etc to tell the Pilot that you are the boss) servicing (Before, After and Inbetween Flights) and basic replenishment (Oils, Fuel, Lubes, Tyres, Oxygen, Nitrogen, Coolant etc) plus a load of other jobs (Yes, some are sh1t!) which will include fault finding.
At some point whether you go back to Cosford or not, you'll consolidate your technical training and start your advancement through the ranks, attain responsibility, gain a love for alcohol, a fierce intolerance of d1ckheads (Unless you are that d1ckhead!) and a solid set of skills to see you through life.