Hi!
To get costruction robots to repair something you need repair packs in your inventory (when you have a personal roboport) or within a roboport.

To get costruction robots to construct something you have to place a ghost or a blueprint within the construction area of a roboport.

Hello, use a decider combinator with output wired to input and configured with Less Than (<). Connect the input with the pulse reading belt. The combinator works as a memory cell and couts up by every puls. When its couts is equal or grater as the Less Than (<) value the output signal will be resett...