Look at these two blog posts on installation:

https://safiery.com/blog/lowest-installation-costs/

https://safiery.com/simple-shunt-installation-caravan-motorhome

Configuration Guide

SC301

SC25QT

Main Battery ✔ (internal) ✔ (internal)
Main Battery Shunt
High Current Dedicated Shunt (like inverter)
Second Starter Battery ✔ Voltage for U1 or U2 ✔ Voltage for U1, U2 or U3
Tank with Voltage sensor ✔ Voltage for U1 or U2 ✔ Voltage for U1, U2 or U3
Pressure Sensor ✔ Voltage for U1 or U2 ✔ Voltage for U1, U2 or U3
AC Current Sensor ✔ Voltage for U1 or U2 ✔ Voltage for U1, U2 or U3

Cabin Air Quality
(Either Dust or Co2 Sensor)

✔ Voltage for U1 or U2 ✔ Voltage for U1, U2 or U3
Solar Performance Sensor (not solar measurement) ✔ Voltage for U1 or U2 ✔ Voltage for U1, U2 or U3
Pitch (Forward and Backwards) ✔ Voltage for U1 or U2 ✔ Voltage for U1, U2 or U3
Roll (Sideways) ✔ Voltage for U1 or U2 ✔ Voltage for U1, U2 or U3
Current Measurement to 25A per channel (combine channels for greater than 25A circuit)

Up to 4

C1, C2, C3, C4

Tank Measurement Ultrasonic with Resistance input ✔ Resistance for R1, R2, R3, R4
Temperature Measurement (resistance) ✔ Resistance for R1, R2, R3, R4
Battery Temperature Included