You have to know how exactly the process of making money.

I am just here to give a general concept of how to actually earn commission.

For Promoting Wealthy Affiliate

You can find the affiliate links in your "Affiliate Program Details". The affiliate links are under the "Links and Tracking".

When you write your website, promote Wealthy Affiliate and talk about topics that relevant to WA. Then add some affiliate links to refer people to join WA.

When they upgrade to Premium, commissions are yours. :)

For promoting other niche

The concept is almost the same as WA. You can get the affiliate links from the platform such as "Amazon". There are tutorials in the Online Entrepreneur Certification and Amazon that teaches you to put the affiliate links in your website.

The overall concept is just build your website.

Add contents.

Put affiliate links.

Earn commission.

Cheers! :)