Need help trying to build and install custom components

Just follow the dev install
linuxcnc.org/docs/2.9/html/code/building-linuxcnc.html
in the terminal window you are using, you will need to type 
. ~/linuxcnc-dev/scripts/rip-environment
Not the leading period followed by  a space 
Closing that window should restore normal deb installed function

I did do a video