To be honest, whatever code you are using, making and altering buttons should be the easiest thing to do, especially as if you're using someone else's code, as there will likely be button examples.
Look for something like ....
{
InSim.Send_BTN_CreateButton("^7Click this button!", Flags.ButtonStyles.ISB_DARK, 5, 30, 6, 108, 7, C.UniqueID, 2, true);
}
Even though I don't have a clue about the InSim protocol and code you are using, I can tell ...
background colour of button - ISB_DARK
likely placement of button and size and spacing of text within button - 5, 30, 6, 108, 7
text colour and message inside button - Click this button! (text will be white)
No idea if this is a button that only a specific person sees, or if everyone on the server sees at same time.