The Custom Panel module is at the heart of the Adroit Custom bundle.
Although it's a small and rather innocent looking module, a huge amount of functionality is packed inside.
In practice you will uses multiple Custom Panel modules butted together and arranged to form a larger user interface. This interface can span multiple cabinets if you require extra vertical space.
When you add a Custom Panel module to your patch it will be blank apart from the TITLE text at the top and the ~Adroit~ logo at the bottom. To add an element to the module, right-click in the blank space between the title and the logo. This produces a large menu of options. Begin by selecting the "Add small knob" option at the top of the menu.
A small knob will then appear with the text LABEL underneath it. Right-click on the knob and another large menu will appear. This menu enables you to change the properties of the knob. Perhaps the most important menu option is "Map to control". Select this option and everything in your patch that can be controlled by the knob will be highlighted in green. Click on one of these target controls, for instance the VOLUME knob at the top of Voltage Modular. The small knob on the Custom Panel module will now remotely control the VOLUME knob.
A feature called auto-labelling takes whatever name the developer gave to the target control in their code and uses it to label your control on the Custom Panel module. In the case of the VOLUME knob Cherry Audio called it "Main Out Volume Knob" but this is too long a label to fit in the space available so it is cropped. To fix this, double-click on the label and type in something shorter like "Volume" followed by return.
There is a great deal more to learn but you have essentially already discovered the essence of how the module works.
As you explore the menus, you should find that your intuition works almost all of the time but extensive documentation is provided on the Adroit Synthesis website should you need help. If you are online while using Voltage Modular then you can access the website help by right-clicking on the top of the Custom Panel module and selecting the Module Help option.
The Custom Look module lets you change the appearance of Custom Panels and the Custom IO module allows you to do all kinds of other things beyond simply remotely controlling knobs, sliders and buttons on other Voltage Modular modules.
See https://adroitsynthesis.com/custom-panel/ for details.