A fully-approved B1.1 Basic Training course would normally have a minimum of 1200 hours classroom work (Modules), 800 hours Practical Training and 400 Hours OJT. Practical Training is carried out by the Part 147 MTO in its approved workshops, which must include a real (non-flying) aircraft for training on, and the OJT must be carried out in a Part 145 MRO under the supervision of the Part 145 and the general control of the Part 147 MTO responsible for the entire course.
If you want to add a B2 to a B1.1 licence you will have to pass additional Modules, as well as work experience etc, but I can't remember what they are. Module 13 springs to mind, but there may be more.
EU 1321/2014 Part 66 Appendix 1 tells all.
If you can find one, you can do a B2 Basic Training course, instead of a B1.1 course. Having only a B2 is not a good career move, these days. You may find a combined B1.1/B2 Basic training course but I'm not sure about that.
Don't forget that if and when you complete a Basic Training course, you get a Basic Training certificate, not a licence. You can apply for that only after completing 2 years work experience, well-documented and relevant, in a Part 145 environment. You have to find the job that will give you that experience.