To mount an already deployed Gatling gun, move behind it, point your crosshair at it, and when your crosshair turns yellow press the “use” key (default “E“).

Secondary Fire disassembles the Gatling gun so you can carry it with you.

You simply need to add the caret character (^) and then a number, as shown here:

^1 red
^2 green
^3 yellow
^4 blue
^5 turquoise
^6 pink
^7 white

For instance, *LAME* Biondo is written: ^1*^4LAME^1* ^6Biondo