Create Smart Playlist from existing library

[AndyBerlin]

Dear all, sorry to ask, as this must have been solved before but I cannot find it: How do i create Playlists from an existing library?
Background: I have a mid-size well sorted library of 10k tracks (all ripped from CDs) on my Synology, that I access via the Yamaha Musiccast App to play at my place.
Until recently, I used iTunes Server to create smart playlists, e.g. "all Pop tracks except from ABBA that are longer than 1:00 minute".
Synology no longer supports iTunes Server, so I I would like to now do this using Asset UPnP.
So my question: How do I create a bunch of such smart playlists in the Asset UPnP web interface, so that I can easily find them later in the MusicCast app?
Thanks a ton in advance!

[Spoon]

Use Dynamic Browsing, however we have no minimum length specifier.

[AndyBerlin]

Thanks Spoon and Muhammawaqar for your rapid replies! Highly appreciated! Very kind.
However, I'm probably too stupid, how do I 'save' dynamic browsing settings so I don't have to manually "create" that setting every time I want to shuffle through all Genre=Pop and Artist=/ABBA? I can "save" these settings, right? But How? I have tried everything in the browser tree overview, but don't seem to be able to type anything. Do I have to go to the plain text option?
I'm sure I can figure it out, if only you could share with me one example so I get the logic. I'll then take it from there.
Huge thanks again!!
My best,