Soil moiseture sensor + Raspberry Pi

Hello guys, sorry i didnt find a forum for raspberry, feel free to move topic to appropriate plase if you will.
I want to use this analog-digital board to convert analog signals from soil moisture sensor to digital and
concume it in my nodejs script.

1. Sensor: https://www.dfrobot.com/product-1385.html
2. ADC board: https://www.waveshare.com/w/upload/b/b7 ... Manual.pdf
3. Raspberry Pi3

So my problem is next: i inserted extension board on top of Raspberry and installed library as
explained in user manual but executing test code
returns next: I think Chip ID must be assigned to some address, so having that in 0x0 makes test fail.
Also i have a little experience with sensor ( before i've used digital only) so in general don't understand where from i should read
converted signal, given that i connect sensor to VCC, GND and AD0 on left side of extension board.
Can someone point me at the right direction?