tomorrow im wanting to drain and refill my coolent i have my mix of 50/50
2.1 concentrate 2.1 water is there anything special i need to do or is it as simple as

unscrew clip

let fluid drain out

get house run water through the pipes

attach house tighten clip and top up

turn on on engine

please tell if i am going to do anyting wrong i do not want to mess up my car

theres at least 3 guides in here https://www.fiatforum.com/punto-guides/

I would have washed it through with the garden hose backwards and forwards. If its really dirty whip off the top hose and thermostat housing. If hose not available use a bucket of water & tundish.

Then add 3 litres of undiluted coolant and top up with water. There will be trapped water in the system & this ensures the final mix is at least 50%.

Better still fill it with water and radflush cleaning solution, Run engine according to instructions then wash it out and refill with coolant. The risk is leaks when the radflush cleans any gunk that had been blocking holes in the rad etc. But better to know the leaks are there (and fix them) than have the rad burst on the motorway and maybe take out the engine.