Depending on your faff tolerance/budget ratio it’s one of those jobs that’s quicker for halfords or boy racer shop to do as they have every conceivable addapter to hand.
Avoid Halfords, I had an Alpine unit fitted by them into my Octavia, the bloke really struggled to fit it, and took two hours when it should have taken 30-40 minutes.
When I replaced that with a Kenwood DAB unit, which I bought from Halfords on an offer, I found a place in Westbury that did audio fitting and window tints, when the bloke there took the Alpine unit out, he asked me who the bloody hell had fitted it, Halfords, I said. Figures, he said.
That unit is still working fine six or seven years later, the only thing I’ve changed is having a mag mount DAB antenna fitted, in place of the stick-on windscreen one. Makes a huge difference to reception, there are very, very few places I can’t get a signal.