Set values ​​for sonata's built-in administrator

Question

I have two objects: Media affiliate partner.

I created my partner administrator and would like to associate an image for each partner.

I just want to upload the file to Partner Admin, and then set the file name attribute (depending on the name of the partner) when I submit the form for the partner.

For example, I want to create a "Stack Overflow" in Partner Admin. I take the Stack Overflow logo, and when I submit the form, I want to automatically create a new medium with the file name "Logo Stack Overflow".

Can you help me?