65ger Mustang start

Hello everybody, I’m new here and I bought my first vintage car yesterday. A mustang from 1965. I’m a complete beginner and I have to read in, but I have a question for you. The salesman explained to me how to start the engine. I feel that I’m doing something wrong, because the engine doesn’t start immediately. (It always works with him) Cold start: Set ignition, pass the accelerator once and let it come back up to half, then start. rmstart: Set ignition, kick the accelerator pedal up to half and then start. I always need 2-3 attempts until it starts … Do you have an idea? Thank you in advance!