That a VERY ambitious project. I've seen other beginners attempt something similar but it never worked out. Usually those attempting to build an RC heli from scratch would be experts on RC helis and very familiar with the electronics needed. If you don't have that level of knowledge then your chances of success on such an ambitious project are almost zero.
A photo of the helicopter might also give us a clue if the project has any chance of success.
However, to answer your question, assuming the heli will be flybarless:
Transmitter with at least 6 channels and helicopter programming . What you go for depends on your budget and what brands you have available locally. Something like a Spektrum DX6 would do the job but there are many choices.
A 6 channel (or more receiver) compatible with the transmitter
A flybarless controller such as a Brain2, Spirit2, Microbeast, Futaba CGT760R, Vbar Neo etc etc (many options)
3 x 'standard' size cyclic servos
1 x standard size tail servo
1 x throttle servo
There are so many brands and models of servo that it's hard to advise. Maybe if you told us what budget you have and what shops you intend buying from that might allow us to make some better recommendation.
