New to Linux-LinuxCNC.... have questions

As I stated in the beginning Im new to Linux.

I'm assuming I have to download & install Linux OS. Then add LinuxCNC?

When looking online there seems to be many versions. which is best for using CNC?

In using the Mesa 7i76E & need to use a 110V device how do I incorporate a relay to handle that type of load or loads?

I have never wired a system from scratch. I've read in the manual. If I understand it correctly i'll have to supply the daughter card with a 12V power source at TB1 "Field Power" then wire out to a separate relay. Is this correct?

Maybe a solid state AC relay?
au.rs-online.com/web/p/products/9032970/...ALw_wcB&gclsrc=aw.ds

You will need to mount it on a heat sink. There are some nice ones that are designed specifically for the component. I got mine off ebay as a set.

You could also use ones like these AutomationDirect - Relays . You will also need the matching socket. I used the single pole 24 volt ones in my cabinet. For a larger inductive load I used a SSR as RODW suggested.
Mounting them using a piece of DIN rail makes for a nice installation and easier changes in the future.

If you get relays with a coil look for ones that draw less that draw less than 60ma. If you get larger ones you will want to install the flyback diodes

From the manual

VOLTAGE CLAMPS The output driver chips used on the 7I76E have built in Zener diode clamps to clamp inductive turn-off (fly-back) spikes. This means that flyback diodes are not normally required on small (less than 60 mA) inductive loads. If high current inductive loads are switched or inductive loads are switched at high frequencies, they must have flyback diodes to limit power dissipation in the 7I76E's driver chips.