Similar to a YouTube vlogger, if you have a large following on Instagram then you could become an Instagram Influencer. You will be paid to promote products in your photos, from wearing certain clothes to action shots of you using particular merchandise. As your Instagram following grows, you may start out simply receiving freebies in return for a picture of you with the item in the shot. However, for those with followings running into millions, you can expect large payments to display products in your pictures. Use sites like Hype Factory to help connect you with companies prepared to pay for your influence.
In terms of coaching, my advice is to try to go it alone for a while until you have specific questions you need to ask, and specific things that are troubling you in your business. Having a coach as a beginner is often a waste of money in my opinion, unless you have the cash laying around and really want to make progress fast. Most people do fine bootstrapping, then get a mentor when the hurdles start to get higher and more frequent.
If the above locations do not yield information pertaining to affiliates, it may be the case that there exists a non-public affiliate program. Utilizing one of the common website correlation methods may provide clues about the affiliate network. The most definitive method for finding this information is to contact the website owner directly if a contact method can be located.