First step would be, that you make Lookup Columns work, that refer to an Document Library
2nd Step: Make them viewable as pdf and activate Feedback columns (like / Rating)
-> Changing them / Uploading new versions would be great as well, but I understand that it might be very hard to implement all those Versioning functionalities as well .....
PowerApps can connect to Document Libraries today. We realize the work needs to be done to improve discovery and usage, and we continuing to work on this.
In the meantime these video tutorials may help:
Massive need for connecting to excel spreadsheet living on sharepoint library. Anybody know of a workaround for this?
any updates on being able to upload to Document Libraries from within PowerApps?
still no update?
Browse different SharePoint sites, display the document libraries on that site, view just about any type of content from those document libraries directly "within" your PowerApps and printed on any device (i.e. web browser, Apple, Android) including PDFs, Word and PowerPoint documents, highly compressed photos, and quite possible many other formats without using SharePoint Lists or Excel workbooks, OneDrive or any other complex hack for that matter. Any file displayed in the app can be downloaded to your local device seemlessly. Notwithstanding how cool and user friendly this app looks.
Teaser of the demo app - now I just need to write the blog to describle how it was developed (and it's not complex code...). I haven't tested yet with handling folders within the app however I am relatively confident I can do include this functionality as well.
Whilst the blog won't specifically speak to uploading files to download libraries, it will include the technique to levarage a SharePoint List with an attachment control that enables you to upload any document as a SharePoint List item attachment following which it will then move that attachment document to the current document library you are viewing in the app (hopefully).