Does anyone know how to create an advertising agency?

Is it possible to make a website video advertising agency advertising apps/games? Just like how companies such as chartboost;adcolony;unity but a website version? Advertising to mobile traffic?

If anyone knows about this stuff and could help would be great!

Thanks guys.

You need a website and payment method and you need marketing towards that website to get clients in. Have you thought about how you will market the website?