You need to look at what affiliate program would be best for your content. You want your affiliate campaign to fit seamlessly into your content.
A good start would be to join as many affiliate networks as possible. Here is a list of the largest affiliate networks (this may depend on what country you are in) https://theaffiliatemonkey.com/affiliate-program-networks/. When you join the networks they will display the best affiliate programs they are running. One mistake beginners always make is they only look at one factor in the affiliate program and that is a commission! The commission is great but there are another factors to consider when picking a program. For example, cookie lifespan is definitely on to look out for! As a beginner I would focus more on converting that making a huge amount of dollars.