What to do
The logical steps for creating a package definition file, typically named package.xml, that describes the dependencies required by your project are:
List what you need - Include in this details such as what channels the packages are to be installed from and whether you only want very specific versions of those packages to be installed, or if you want to specify what the minimum versions of the packages should be.
Create a package.xml including these packages as its manifest.
Test that it works