Before I go into the training, your reference to 'class angels' stood out to me and not in a good way. Be careful here - you will need to teach/help all pupils, whether they are 'angels' or not!
Anyway, on to training.
Training courses start in September. Depending on subject, you probably still have time to apply for this year.
You can either do a SCITT or a uni based PGCE.
SCITT trainees are in their home school from the start of September. Usually 4 days a week at first with one day in centralised training, but it can vary a bit from time to time.
Uni based PGCE usually do a few weeks in uni before starting their first placement in schools.
Both courses include a contrasting placement in a second school and both would build you up gradually with the teaching.
The SCITT I do some work with starts trainees off with observations, then doing small parts of lessons and then teaching a full lesson by week 4. In placement one, they usually end up teaching around 7 full lessons per week.
Placement 2 (Jan-Easter) builds quite rapidly up to a 60% timetable.
Final placement is 1 week observations and then 80% timetable.
You will also usually be attached to a form group, shadow break duties, be involved in the wider life of the school, attend INSET days/department meetings, parents evening etc.
As much as I love the job (I'm a HoD now) it is tough and the hours can be long and the workload high. Everyone manages this differently but most people either get in early or stay later or both. It's a full on and very demanding job, so just make sure you are prepared for that!