Although it isn’t mandatory, you could choose to add a note in your FAQ/Help section, informing visitors about the new ads they see. This notification could also work as an introduction to In-Page ads and inform users about ways in which they can interact with them.
For instance, you could add the following paragraph to your FAQ/Help section –
The ads appearing on the home page and subsequent pages of the website are In-Page ads by Affinity. Affinity’s system scans the content on a webpage and places relevant brand messages on dedicated ad spots of the webpage. You could choose to click on the banner ad or link provided in the ad to visit the advertiser’s website.