Hello and welcome to the forum 
For photoshop brushes, see the following topics:
How to import photoshop brushes? and
this Help w/ Importing ABR Brushes
Essentially, you can’t do it and all you get is the brush tips, which you can then use as part of a krita brush preset.
For your problem with importing a krita .bundle file, which bundle did you get from where? What exactly did you do with it?
Does it show in the Active or the Inactive bundles of the Manage Resource Bundles window?