First-time installation on WRT1900ACS v2 --- **am I right?**

I read for hours in order to be prepared for the 'Factory install' procedure - I'm not sure if it was enough.

Downloaded this:
checksum is ok.

Will there be all the components which are named in the LEDE documentation? or is that a basic version?
after hours and hours I could'nt find a list with what comes with or even not. But I found the 'User Guide' with the 'Basic configuration' - it seems a bit to do and if that would work fine, I would be glad.
If anyone reads this and got a hint for me - thanks a lot.

At least go for 18.X or preferably master/trunk, you're going to have very bad experience with 17.X on a mvebu platform.

Which components? Which documentation?

Unlike some other router firmwares, with LEDE/OpenWrt you can easily add packages (like you add apps on your smartphone) to add functionality.