Crew Training



Okay, crew training is a bit confusing to me as I started playing WOT with the Blitz mobile version. I found PC version a lot more challenging and thus I started playing it but crew training is still confusing me. in Blitz it was a simple "crew" instead of individual crew members and there was a train one skill for the entire crew depend on tank type at a time. now there are so much more options. can some one provide a BASIC and CONCISE explanation on ALL crew mechanics and researching options.

specific questions I have:

1. am I only allowed to train crew skills AFTER they all reach 100%?

2. I want to speed up the process of going from 60% to 100%. How?

3. How many skills can you train per crewmember?

4. Does anything carry over if you move a crew to a different tank? (e.g. Chaffee to T37)

5. off topic but WHY do modules cost credits? in Blitz, once you research a module, it's automatically mounted. now grinds are EVEN longer than on Blitz