Which Glue to stick fabric/plastic/metal?

[Doran]

I've been tasked with helping my Niece with her shiny new phone, can anyone give some advice before I bork this up?

She has a new phone cover, which is plastic with polyurethane leather (which is not smooth) and she wants to attach a ring holder to it - which is metal with a 3m adhesive pad (sticker can be removed if need be to make this work).
The sticker isn't adhesive enough to attach to the lumpy PU leather, so am looking to glue it. or to make a surface on the case smooth enough to stick the adhesive pad to

Would bog standard contact adhesive work? or super glue? or something else?
I'm concerned about the PU leather melting if using the wrong glue

Any help appreciated

 

[foxhole]

Have used contact adhesive and also araldite , both work.

 

[cdbe]

I just cut a hole in the back of the case with a holesaw and stick (in my case metal discs for car magnets) it directly to the back of the phone - stops the thing sticking out as much as well.