Hello and welcome @vanwerk
Start with the template.
It is much easier to layout the panel and drill holes in the box first.
When that is finalized, place all the socket footprints in appropriate positions on the PCB, then the other footprints, and finally the tracks.
There are several methods for exactly locating your footprints that are accessed through the holes in your enclosure.
- Place the Grid Origin point and read the X & Y values
- Use dx & dy.
- Use Right Mouse Click “Selection” > Positioning Tools.
This Moving the Global Grid thread from just a few days ago will be of use to you.
If you have any questions on using any of these functions, please ask. 