Default applications in linux open suse leap 15?

Description:

Have linux open suse leap ~15!!!Can't open org.kde.discover.desktop file which located in /home/etc/Documents/Apps/ in folder by created me.

Problems:

1. May be I removed something and now any (AnyApp.desktop) is could not opened in my linux system.This is my 1'st problem today.

2. Snapshots is not working also.

I Try:

1. And when I was try opening any .desktop file by (double click) it just was opened with libreoffice application (calc) but it's impossible.
2. In Settings/Applcations/No any workable associated application. (except for the calc).