Halo! And willkommen!
Good to hear she's already accustomed to peeing and pooping outside. That's a great start! As for the issue with her peeing indoors...she's not doing it on purpose. At 3 months, she will go whenever she feels the urge (at least in the very beginning anyway since everything is new to her). I know exactly what you mean about no sign though - they just walk and suddenly squat and pee!
I would keep her tethered to you at all times when she's indoors for now (at least for a few months). Only let her run around a little right after she went potty outside - for as long as you're able to watch her every move. Once you need to do your own thing at home and cannot watch her every move, keep her tethered to you or put her in a crate or a playpen.
If you want to have her completely outdoor potty trained, I'd suggest a crate. If you would consider having potty pads indoors, then you could put potty pads in the play pen.
You may need to get a new bed. Once the pee scent is there, she'll always go back to it for pee. Or...drench it with a good enzymatic cleaner that is for the purposes of removing all pee scents. In N. America there's a brand called Nature's Miracle that works really well.
If she's only been with you for a month, let her take the time to get used to things. If she doesn't want to sleep next to you, just let her be for now. She'll bond with you soon enough. Or maybe because the bed has pee smell? That's why she's sleeping on the floor? But at night, I wouldn't let her roam freely. For potty training, you should really crate her or keep her in a play pen.
With new puppies, it's a lot of trial and error, especially since every pup is different.
And we all understand your English just fine! kein Problem
