RevenueCat FlutterFlow integration purchase

Hello. I would like to ask for help. I have a problem integrating purchases with RevenueCat in FlutterFlow. I searched the documentation, but it is very poorly and unclearly covered regarding sales. For subscriptions, I found a lot of information, but for sales, it is very sparse and unclear. My app is already running on a website, and I use Stripe for payments there, which works fine. When I started with RevenueCat to set up the app on Google Play, I thought it would be similar, but it does not work. I am selling credits, like lives in games that get consumed later. After a purchase, the credits should be added to the profile of the user who made the purchase. I am using Firebase as the database. My main problem is with sales. I have connected RevenueCat and Google Play Console, and I think that part is okay. I believe the problem is on the FlutterFlow side, but there is very little documentation, or it is too general. Does anyone know where I could look? Has anyone had a similar problem? I installed the app on my phone, and when I try to make a purchase, nothing happens. I also changed the product ID thinking that was the issue, but I don't know what else to try. Thank you all in advance for your answers.