I'll give you Free advice for improving your UI/Design

Okay, checked it out.

1. You have some kind of disharmony in colors and fonts. In the header I wouldn't use blue links. And I wouldn't use Helvetica, too standard, looks a bit old for me.

2. Maybe instead of using macbook mockup I'd just put screenshot with borders, since you kind of lack space, macbook looks excessive

3. Make borders for all of your pictures. Because those which don't have them, looks a bit weird https://prnt.sc/twoa8r

4. Again, disharmony https://prnt.sc/twoam5 , make picture smaller, text bigger. Use only one heading + text, no need for heading + subheading + description

5. https://prnt.sc/twoavl The picture is larger than the screen but the text is way too small

Okay let me show you some corrections:

https://prnt.sc/twod1a . Yeah, screenshot looks small but this is more a problem of screenshot. Show some main part of application, make it clickable. Usual trick is to remove unnecessary elements from screenshot, like doesn't have to be exact screenshot of your app, it should explain the feature

Hmm, it's sad that you don't have version for Mac, since I wanted to check it out myself. Not that easy to give application advice only by viewing screenshot.

1. https://prnt.sc/tsg2p0 Alignment is broken
2. https://prnt.sc/tsg31v For me the "Beta" label is placed weirdly. I'm mac user, maybe that's what I also think that version should be hidden somewhere in "About" menu, along with beta and other stuff (like contact us etc)
3. https://prnt.sc/tsg40q I'd limit the label width and if path overflows the width, I'd add dots, like d:/users/somepath/filen...
4. I know I cannot think and provide some concept but here is caught my eye that it should be aligned as well https://prnt.sc/tsg4ot
5. https://prnt.sc/tsg562 Maybe it's more natural to have "<<" and ">>" buttons, not sure about this
6. https://prnt.sc/tsg5mp Here you have 3 squared buttons and one not. Some disharmony

But you know what, it's an app and it's Windows app so I may be wrong. The only 100% thing I'm sure about is p.1 and p.2, especially the first one is easy to notice and easy to fix, label alignment. Also, https://prnt.sc/tsg6i1, is it okay? Looks a bit buggy too