Once a custom Fork of Monero has been created, what are the steps for allowing "people" to be able to buy the currency online?
Does an exchange need to be created or is it a case of approaching an existing exchange and "working with them"?
If you create a coin, people will mine it. Once they mine it, they will get coins as a reward. You then have to negotiate with exchanges to list your coin or in a best case scenario they will list the coin for free.
After they list the coin, people can buy / sell them.