Where to Start?
A good place to start is either selling on a free or paid platform or if you don't wont to use little to any money you will have to dedicate more time instead.
Clickbank is a good place to start it has many digital products and some tangible you can chose to be a Vendor or a Affiliate depending on your budget and expertise. Affiliate is the most common route for this platform, basically you are the middle man to the Vendor and its customers which are found by you and sourced to the Vendor then you will obtain a commission on that product if it sells or converts.
Now this is when you start to market your chosen Vendors product and services, this can be done for free by using a multitude of different platforms and internet tools to achieve traffic to your chosen Vendors offer. Obviously the best known platforms are the social media, public domain sites which have a far reach to a world stage Influencers and Advertisting companies use these platforms to generate traffic either to themselves or there product and services.
In a nutshell it is a mass Selling Arena which give everyday people billboard to the world so they can promote themselves or there business to gain customer awareness and ultimately to make a living out of being online.
There are many techniques plus software tools and platforms to make you able to sell with Affiliate Marketing, these can be found on Youtube and other social media platforms and general Google searches obviously you will have to do extensive research.
Check the Youtube video below for more information on this subject below.