Clueless how to.. Advice needed

My SO wants me to initiate sex. I'm really nervous and have no clue how or when or where to start. He normally does it and I'm scared because what if it doesn't work? I need to feel confident and sexy in order to do that and lately I just don't feel hot. Do you ladies have any advice you could give me to not make me so nervous or tips that you use to get your man going. Thanks!