Planning: Casting

In order for me to organise this fairly easily, I will use actors that I am familiar with and are therefore around my age. I know people who attend drama lessons and I am going to attempt to use them in my film. The main character for the opening part of the film will be a male and I will need two extra actors to play the scientists, those would preferably be one male and one female, but it does not matter if they are both male either.