Package not built correctly

I am new to Launchpad. While experimenting with creating and publishing a package, I had followed the following steps:-
1) Create PPA tempest related to my account.
1) Make the folder structure with both debian and DEBIAN directories to build for both launchpad and local .deb file
2) Used debulid -S to build files from source.
3) Used dpkg-deb --build mdcd_1.0.1_all to build deb
4) Upload changes file using dput -d ppa:ishan-surana/tempest mdcd_1.0_source.changes
The relevant tree after following the steps are as follows:-
.
├── mdcd_1.0.1_all
│   ├── debian
│   │   ├── changelog
│   │   ├── control
│   │   ├── files
│   │   ├── postinst
│   │   ├── prerm
│   │   └── rules
│   ├── DEBIAN
│   │   ├── changelog
│   │   ├── control
│   │   ├── postinst
│   │   ├── prerm
│   │   └── rules
│   └── usr
│   └── bin
│   └── mdcd
├── mdcd_1.0.1_all.deb
├── mdcd_1.0.1.dsc
├── mdcd_1.0.1_source.build
├── mdcd_1.0.1_source.buildinfo
├── mdcd_1.0.1_source.changes
├── mdcd_1.0.1_source.ppa.upload
└── mdcd_1.0.1.tar.gz

Note that the usr/bin/mdcd is a shell script that is the actual code I want to run/install in the relvant path. Hence, when I test local install using sudo apt install ./mdcd_1.0.1_all.deb , and it got installed correctly in the relevant path
$ which mdcd
/usr/bin/mdcd

However, on the Launchpad build, things seem different. I couldn't use the mdcd script after installing and the post install script had also given error related to this (/usr/bin/mdcd not found) while installing from apt using my PPA. On donwloading the deb build from PPA builds and inspecting, I saw the issue:-
.
├── DEBIAN
│   ├── control
│   ├── md5sums
│   ├── postinst
│   └── prerm
└── usr
    └── share
        └── doc
            └── mdcd
                └── changelog.gz

This is the tree formed. My source code is not there anywhere here (/usr/bin/mdcd). How do I fix this ensuring my package is uploaded/built correctly?