Smath snap attempt

snap
1

Looking at Popey’s video snaps looked easy. however, snapping my favorite mathematical editor was a bit more difficult than I anticipated.
So far I got it to download the files into the snap and extract them but the command can’t be reached and I doubt about if the gui will work in the end. documentation seems to be mostly focussed on the easy straight forward snaps. Could some one point me to how to continue from here?

original project can be found at https://smatch.com

My current yaml looks like this:

OBSOLETE
2

Well I have been able to make slight progress in that now the build completes without any errors. however when i test the snap it fails.
current yaml:

name: smath
version: 0.99.7030
summary: SMath Mathematical program with WYSIWYG editor
description: |
 Tiny, powerful, free mathematical program with WYSIWYG editor and complete units of measurements support. It provides numerous computing features and rich user interface translated into about 40 different languages. Application also contains integrated mathematical reference book.
confinement: devmode
base: core18

parts:
   smath:
     stage-packages:
       - mono-runtime
     plugin: nil    
     override-pull: |
       wget --post-data "RefMem=&PostBack=5TGzK" https://smath.com/file/5TGzK/SMathStudioDesktop.0_99_7030.Mono.tar.gz
     override-build: |
       mkdir $SNAPCRAFT_PART_INSTALL/smath
       cp SMathStudioDesktop.0_99_7030.Mono.tar.gz $SNAPCRAFT_PART_INSTALL/smath/.
       tar -xzvf SMathStudioDesktop.0_99_7030.Mono.tar.gz -C $SNAPCRAFT_PART_INSTALL/smath
       chmod +x $SNAPCRAFT_PART_INSTALL/smath/smathstudio_desktop_mono

apps:
    smath:
      command: smathstudio_desktop_mono

And the terminal output:

Staging smath 
Priming smath 
'grade' property not specified: defaulting to 'stable'.
Snapping 'smath' /                                               
Snapped smath_0.99.7030_amd64.snap
tom@Airhover:~/mysnaps/smath/snap$ ls                                           
smath_0.99.7030_amd64.snap  snapcraft.yaml
tom@Airhover:~/mysnaps/smath/snap$ sudo snap install smath_0.99.7030_amd64.snap  --devmode --dangerous
smath 0.99.7030 installed
tom@Airhover:~/mysnaps/smath/snap$ smath
Cannot open assembly './SMathStudio_Desktop.exe': No such file or directory.

So the smath_studio_desktop_mono command is a shell script that points to the executable file therefore I am hopeful that it is almost there.
However since it didn’t land in debug mode anymore how to check why it can’t see the executable?
from the tar it should end up in the same directory as the script.

Any thoughts?