Program Arduino or similar

I need to read 4 x thermistors (10K3A1) and 1 x flow detector (simple switch) in a heating system, and depending on the relationship between the readings, logically control 2 x relays (these will open/shut 230V water valves).

I will need to have visibility of the temperature readings and the relay output status, and be able to adjust the temperatures, dead-bands, minimum change-over time etc.

I have the sensors and the relays but need advising how to get permanent connections to whichever processor we are going to use, rather than via a breadboard