Questions

I have created a free wrap of my wordpress website.
I cannot get playstore console to accept it. It says that the median app has the wrong SHA-1 certificate.
But there is no where in my Median app to enter this.
So is it the case that one cannot upload a free app to Playstore?
If it is possible, can you provide guidance/video etc., as to how to upload the AAB or APK (I assume only the latter with the free version?) into Playstore.
Thanks for your help