All programmers in mql5 have to read all these 4200 pages? or just some structural parts, and you will be able to program anything. If there
are just some important parts what's important to read on documentation in order to program anything? thanks
An amount of reading and learning depends on your previous experience as programmer/developer and trader.
Knowledge about software development and trading will reduce the time needed to learn.
Although, if you want to be an efficient coder, you have to get familiar with all aspects of the platform.