Difference client- and server-side?

[WickeTD]

I'm trying to open a Derma menu whenever a user uses their secondary attack. I have a function DrawDerma() which, obviously, contains the code for creating and showing my Derma controls. However, the functionality within appears to be all client-side, and TOOL:RightClick() seems to operate server-side, even though the documentation says it's shared. That's what confuses me. I'm still fairly new to GLua, so how would I go about this?

function TOOL:RightClick(trace)
	DrawDerma()
end

[CGNick]

Doesn't get called Clientside in Single Player.

[WickeTD]

Then how am I supposed to test it?

[.\\Shadow}]

Change "Singleplayer" to "2 slots" to make it a listen server?

[Bobblehead]

If nothing else,

ply:SendLua([[Your code here.]])