I have a openbuild machine and the builder didn't add the limit switches. I've watched a video on this and have a couple of questions. To get the GRBL to know that the switches are installed, and react correctly when hitting one, do you JUST change $21 to 1, or are there other steps? Once the switches are installed and GRBL knows that they are there, does the home feature automatically work? I'm using Bcnc with a Raspberry Pi3. Any direction would be appreciated.