2015 setting the clock

Spring is on the way & we have to turn our clock forward 1 hour. I've had my 2015 C3 Picasso Platinum Blue around a month. I've always found it difficult to see the display with the date & time probably due to the light from the glass roof. It went in for a full service a week ago & earlier this week I noticed the date & time were correct, but the day was one behind. Tuesday when it should be Wednesday. I have a PDF file of the owners manual so I set to to teach myself how to re-set the day. After 4 hours toiling, I still couldn't fathom how to make the change. So I waited until it was dark, went out to the car, started the engine, switched the interior & exterior lights on, & checked which system was fitted to my car. It wasn't the one I thought it was, & the manual was a little short on which was which. Eventually I realised the clock was re-set via the radio controls. The menu button was part of the radio fascia. Unfortunately, this was in darkness, so I went inside & got a torch so I could see the controls easily.. So to start you off, press the menu button, then the r/h arrow on the circular bezel, until you get to the section on the screen next to the speedo relating to the time date & language. Then it's just a case of, pressing the centre button when you reach the setting you want to change, using the up, down, left & right arrows to get the setting you want, then press the centre button to fix it. To leave the menu, press the angled arrow.