DockerPi 4 Channel Relay

How do i get a DockerPi 4 Channel Relay HAT ( EP-0099 - 52Pi Wiki ) to work as a relay should work on my Raspberry Pi with Venus os??

Im not so experienced in programming and it would be nice if someone had a manual on how i get it to work and being controllable from the gui.

I have mounted solarcells on a friends RV and a Victron MPPT 75/15 to control them but now he want to have a RPI with Venus OS and relays that can help him to control some of the functions in the RV, its a Knaus 625 from 1990 that are in fantastic conditioning inside. Im changing all internal flouresent lights to LED and has also mounted USB outlets on several places in the car.

Would it also be possible to integrate a sensor that can give a alarm if a waterleak happens or if the car have some leaks from the roof or around the windows? Many old european RV:s has the Calira Bord Control systems in them with tanklevels that has 5 resistive cables that can tell the tanklevels and it would be nice if we somehow could read those values in Victron OS also, but i dont have a clue how i would accomplish that.

I have looked at the german Pekaway Vanpi system that can read values from the Victron 75/15 MPPT controller and that system can also control other wifi products like “Shelly”, that way the system are really nice, and it can also control several different Diesel heaters, the sad thing is that they makes their systems as really expensive DIY products where you add a RPI to their products. The point with DIY is its cheap against a big manufacturer with lots of employees that want the big bucks to live. They are also German speaking with poor understanding that German is not a language spoken by everyone. Lucky now when the computer can translate much better. 2 years ago i did order from them their big controller but they refused to sell it to me just because i accidently say to them that German is not spoken everywear… so they cancelled my order of 600 Euro….

So now im more intrested in Victron system even that they are also expensive but you get top notch quality from that, i was really happy when i found out that some guys and girls had made a implementation so you could build your own Victron controller with a simple Raspberry Pi with the standard screens.

Anyway, i would be happy if someone could guide me to how i can get the DockerPi 4 channel relay to work without to much hassle so my friend can get back his Knaus RV