Hi,
Can I get a list of the hardware you are using?
So far I can gather/guess that you have
- Tinyscreen OLED Tinyshield
- Adapter Wireling Tinyshield
- Moisture Sensor Wireling
What processor board are using? You mention "Arduino Pro or Pro Mini" which I assume means you are using the TinyDuino. If that is the case, this will take more investigation.
Anyway, make sure to follow your processor board's tutorial: https://learn.tinycircuits.com/Processors/TinyDuino_Setup_Tutorial/ (use the left panel to find your processor board) so that all relevant libraries and board files get installed.
If you want, follow the tutorial here https://tinycircuits.com/blogs/learn/soil-moisture-sensor-animation (should be a copy from the link you provided) using this example https://github.com/TinyCircuits/TinyCircuits-Main-Site/raw/master/Soil-Moisture-Monitor/program/Soil-Moisture-Monitoring_example.zip project.
Let me know what processor board you have,
Thanks