Install linuxcnc on my Pi3B+

I would like to run Linuxcnc on my Pi3B+. But did not succed the installation. Tried to install with usb key, but didnot get anywhere.
I bought a micro SD card, but how can i load the install files on it in proper order?
I'm not a Pi specialist, neither Linux. More a workshop man!
Actually my Pi runs with Rasbian, having used the joined NOOBS to launch it.
However I find nowhere any mention of Rasbian running with linuxcnc.
Is there anywhere a description on how to install Linuxcnc on my Pi?
Thanks in advance for your response
Martin

I'm running LinuxCNC on several RPi's but with an external board for real time step generation.

Check out my instructions.

scottalford75.github.io/LinuxCNC-on-RPi/

Regards

Scott

A good starting point would be one of the pre-made realtime (preempt-rt) SD car images from RealtimePi.
github.com/guysoft/RealtimePi