Thanks,
There is a small problem I'm facing is how to handle the installer bash script?
how can I run it during installation? Its function is to install python dependencies,
You can't. In packages you specify other debian packages to install, they must exist in debian.
For other files, during package creation you create/copy files in a a dir representing the final install (/usr... /var...) and at package install they are placed in those locations.
There are rules where to place files etc.. in debian package policy.
As it seems it is python based, you should first package your soft as a python package + desktop files etc...
There are some helpers to package for debian python packages
creating configuration files and desktop shortcut. Please have a look at it