I'm sorry but this is going to sound very disrepectful, but I can't think of another way to put it. How can you be the R in a game and not know when to start/stop the clock or know your penalty enforcements?
Afterall, the R should be the most knowledgable official on the field. If you don't know these items, I suggest your spend copious amounts of time reading rules 3 & 10 before the game.