It looks like it just doesn’t work.
It looks like you cannot create/combine/organise pdfs, but only open a file that’s already on your device and highlight/underline/strikethrough the text or add new. The pencil sketch is buggy, the strokes just don’t “stay on the page”, while the signature works, more or less. The app as it is seems quite useless, given that the functionalities that work are already available on the device without installing anything at all. Is this a beta testing or did I miss something?