That is the app I'm using. I have the pro version and it is working like a charm with my network drive. It remembers the network name of the drive as 'recently used' on the first screen. One tap on that and I'm able to browse the entire drive, open files, etcetera.
A downside of the Apple system is that you can open a document this way, letting FileExplorer open Pages for a Word file for example, but it may be difficult to get a changed file back to the network drive (I have never tried that). Once a file is in Pages though, it can be automatically backed up in iCloud (depending on your settings) so that the file remains available both in the cloud and on your iPad. You'll have to let the idea of storing files in one place (on the network drive) go if you want to edit them as well.