USB Drive App Problem

I have bought and downloaded the app so that I can view and open PDF and word docs on my IPad 3. Unfortunately the app does not appear to offer that option even though the description suggests otherwise.

I have managed to download files from my PC to the Ipad using the app and they appear on a list. However, whether it is the complete file or just the file name I cannot say. The app does not then allow me to open and/or view the file. If I select a file it cannot be tapped open. The edit function on the app only allows select, select all and delete. There is an option to create new folder but even that doesn't appear to function as it does not save anywhere and/or appear in the app.

Basically I am frustrated by not being able to do what I thought was the purpose of this app.

Happy to0 receive any suggestions and guidance in case I am too thick to use properly. Or can anyone suggest an app where I am able to download (largish) pdf and doc files etc so that I am able to open and view on the Ipad. To be able to do some basic editing will be a bonus. Many thanks.