Headunit upgrade - wiring novice!

Hi guys and girls, it's been a long time since I've been on here!

I have a 2010 Altea XL SE TDI and have bought a Pioneer SPH-DA120 touchscreen Apple CarPlay head unit.

Now, I've done some searching on here but have got myself very confused. I see people have fitted this unit in other models but not specifically my model of XL.

Basically looking for advice on which adaptors to buy to retain the steering wheel controls. I know I'll need an aerial adaptor too but again, which one?

And recommendations for the fascia, aftermarket or go for a genuine Seat part?

Any help much appreciated!

Thanks for all the advice, thought I had replied!

So I went to fit the kits, leads and stereo work perfectly but I had a problem with the Connect 2 fascia. Firstly it was very very tight, and two clips broke when putting it in so that's going back, but also, I couldn't fit the Pioneer HU trim piece when the fascia was in and vice versa, couldn't fit the fascia when the trim piece was fitted.

Any ideas?

I've read that Seat do two surrounds, one with rounded corners for RNS style units and one with right angle corners for aftermarket units. Anyone shed some light on this please?

Couple of phone calls to Seat and TPS and they only quote for rounded corner ones.