This will help, this blog post has a pretty good explanation of how affiliate links work, they will work exactly the same whether they are on a blog or on an instagram swipe up, https://www.wardrobeoxygen.com/how-do-blogs-make-money/
Anyone still convinced someone like, Mrs Hinch for example, is just sharing stuff out of the kindness of their heart, needs to read that link, to understand how much profit influencers really make.
It’s not just all this stuff about affiliate links and ads etc for me. My eyes have really been opened about privacy and sharing photos. I have private SM accounts due to my job but I spent an age last night checking and double checking my ‘online footprint’ and security settings. I genuinely find it shocking that these influencers (be them big or little) share so much of their lives. I practically know the layout of their homes. And all those photos of their children open to the whole world. I would not want just anyone being able to get hold of photos of my daughter and so spent time ensuring everything was set to friends only - and rechecking my friends lists to make sure they all actually are my friends. So now I only have about 15 friends/followers... the influencers’ nightmare!