Answer:
he can use a random sample or a random number generator which is a tool for making or generating numbers with no pattern to make a good representative of that population but it can be more if you want. He can also choose three people or more by asking them to raise their hand who wants to be a volunteer and do not raise their hand if they dont want. So hopefully those are the two ways.
Step-by-step explanation: Sorry if i get it wrong but i tried my best i had.