Your new package is there! You can edit the package properties in the package manager. Use the edit button in the upper right corner of the package details panel to open the package editor.
Here is what you should do:
Of course, the most interesting thing is how to edit the technology definition. When the package was initialized, a folder hierarchy consisting of a tech folder containing a technology definition file and empty "libraries", "macros", "pymacros" and "drc" folders was created. You can use these empty folders to put your own files there. The technology definition can be edited in the technology manager where you can find the technology as "new_tech" under the name you had given the package. Initially, the technology definition is without any particular definitions.
In the package details you will find the local path to your package data under "Installation". You can use any versioning system to manage your files there.
Once you have finished your package, don't forget to specify the package version so users of you package will be informed of updates. Finally you can publish the package files to a place of your choice and submit the download URL to the Salt Mine server.