How can I do this? Millis and conditions

Yes.

Read analog sensor https://docs.arduino.cc/language-reference/en/functions/analog-io/analogRead/

Less than https://docs.arduino.cc/language-reference/en/structure/comparison-operators/lessThan

Greater than https://docs.arduino.cc/language-reference/en/structure/comparison-operators/greaterThan/

Counters How to Make a Counter in Arduino | Delft Stack