Time select in audio

Quick question that hopefully someone knows the answer to. 

I use my pen mainly for storing audio (I have a large (read 80-90GB) audiobook collection and can’t fit a tenth of it on my phone).

The books range from 10-66 hours long, with 1 file per book. The app doesn’t seem to support remembering where you are in the file, so what I was planning to do was just remember roughly where I’d left off and scrub the file to the right point.

Problem is, it doesn’t seem to support that either. I can skip to the next file, but can’t choose to scrub the file to 2 hours in, which is a real inconvenience as it means I can’t use the drive for what I actually intended it to (it never occurred to me that I wouldn’t be able to use the slider to find a time in a file, its been such a basic thing of digital media since I got my first PC in the 90’s).

Am I missing something or is the app actually that limited? If so, does anyone have any suggestions?

you can use the slider/progress bar to move to any point in the song. I do not have any files as long as yours but this works for regular music. a few things i have noticed is that when the slider is to the extreme left you may accidentally swipe the entire screen to the right and go to the previous page. To avoid this just be careful that you are starting with the slider bar and not the actual page. Also there have been a few time where after the phone was locked it would take several seconds before the app become responsive. but that has only happened a handful of times in my experience.