how to install .deb or .rpm file in arya linux
 

There are some packages which i need in arya linux to install in my personal laptop e.g. slack which is only available as .deb or .rpm and source tar balls are not available. How this can be addressed in arya linux ?

source tarballs are usually available. for example you can see here: https://packages.debian.org/stretch/editors/apel on the right side (download source package).
you can search for source packages here too: https://www.debian.org/distrib/packages#view