Avnav is a fast, web-based chart plotter that is optimized for touch screens
Download latest release of https://github.com/openplotter/openplotter-settings/releases and change to the directory where your download file is.
sudo apt install ./openplotter-settings_2.xxxxx-stable_all.deb
From openplotter-settings you should install [openplotter-signalk-installer].
Clone the repository:
cd ~
git clone https://github.com/openplotter/openplotter-avnav.git
(Make your changes and) create the package:
cd openplotter-avnav
dpkg-buildpackage -b
Install the package:
cd ..
sudo apt install ./openplotter-avnav_x.x.x-xxx_all.deb
openplotter-avnav
Or start Avnav from the menu (same place as openplotter-settings).