Your friend that advised you on this should have been the best to fully sit you down and explain how the whole processes works, because you cannot expect someone here to write a whole full book on how you can create your own cryptocurrency and how you can manage it, but the only summary I can give you is that you must first a great concept that you can turn to working product, and ensure that whatever idea you have will be needed and is not saturated already.

After that, document it in a whitepaper, higher a developer that will develop the blockchain for you, and then if you have money to fund it yourself, go apply to exchanges that will help you list it for it to become tradable, and then you still have to create lots of awareness for people to be able to know your coin and for you to get the volume needed for the coin.