Take this as a rough guide only as I did the DEC course many, many moons ago!
About two days of Admin, getting IDs, signing bonds etc. etc.
Commence ground school, CBT, three to four weeks including the final exam.
A week or so of Safety & Survival (including a swim in the pool!), performance, fuel planning, flight planning and air law.
During the above you will be expected, with your partner, (they pair you up, don't bother to ask!), to have familiarised yourself with the check-lists using the 'Cardboard Bomber'.
About eight sessions over about two weeks, (subject availability), of fixed base trainer. It used to be done in the SIM and some instructors would switch the motion on after about the first two sessions, which is a bonus.
About eight to ten sessions of full SIM including base check, IR, CatII/III.
I was lucky and did seven circuits in the actual aircraft, nothing like flying an empty 744 round the circuit!!! Not sure if this still happens or if you go from Full Flight Sim sessions to line training.
Expect to do a Europe, USA, Australian and a couple of local trips, probably adding up to a dozen or so sectors flown as PF/US, could be more, before a final line check.
From day one to 'released to the line', not less than about four months, it all depends on the availability of SIM, aircraft, instructors etc. etc.
Training was very positive, they want you to pass, don't bother telling them how you did it in your last airline!!!
Just a rough guide only as I'm a bit out of date now.
Best of luck.