RTS type Build Menus

Hey guys, Im trying to make a build menu for an rts that you click on, it runs some resource checks, and then waits for you to click and it builds at that location. Ive gone through all of the GUI.Button types on the scripting reference and gotten the resource checks to work, but they all build the structure immediately when i click the button. Is there one that will wait for me to place the building, or do i need to put in a yield type command in my GUI.Button script for it to wait for an additional user input

or do i need to put in a yield type command in my GUI.Button script for it to wait for an additional user input

That's it.

The order typically goes user clicks button -> resource checks -> put game in "place structure" mode (some kind of object following the cursor) -> user clicks to place -> check if place is valid -> start building structure.