cd into your tweak folder and start the theos-templates-menu with
/opt/theos/bin/nic.pl. Choose the
preferencebundle option and follow the wizard. I prefer to use my tweaks name here with the additional "prefs" at the end. In my case it becomes "com.jontelang.sliderchangerprefs".
Once done your tweak folder should now look like this, with an extra folder inside it.
There have been some changes inside the
makefile also which you can look at, although it is not very important at the moment.
By now you should be able to just
make package install to verify that there is an additional entry with your tweaks name.
It should look something like this.