I am an electrician by trade & we installed our own . Flow & return ppipes from the cyclinder , a pressure relief valve on the roof & air vent. We were building at the time so we made up bracket to mount the panels on & got the carpenters to install them when they were slating. Filling loop , pressure guage , non return valve and a box of connetions.
Electrical , power supply for controller , 2 core cable to the sesnor on the controller, 2 core to the sensor on the tank , & circulatineg pump.
The pipes need to be copper and covered completely in heavy duty aramaflex ( qualplex or any type of Pvc will not do as the temperature fthe water/glycol mix can go above the melting point of the pipework if the ESB went off)
Striaght forward bit of plumbing and you will need to get a pump to pump op the water glycol mix ( on hire for a day about €20.00)