Static a big issue?

I am currently visiting my parents house so I had all my new pc parts delivered here because my flat is in an awkward place for deliveries (the address isn't actually registered at the post office). My flat at home is covered in carpet and I've heard that its better to build on hard wood floors or something that isn't going to build up static electricity so I wanted to ask would it be safe to Put the motherboard and cpu in to the case now and then put the case back into the box and take it in the car back home or would I generally be okay just taking all the parts home and building it on my carpet? 

Just ensure you touch something metal to discharge before you take anything out of those anti-static bags. You can discharge on the metal parts of your chassis. If you place your PSU in your chassis and leave the PSU plugged into mains power, I believe that will act as a ground.

I build computers on carpet all the time, it isn't a huge deal.

As long as you are grounding yourself while putting the motherboard and CPU in your case you will be fine. To ground yourself just touch the metal of the case before and while handling your parts. Yes it will be safe to put your components into the case then take the case, box it up, and take it with you.

Plugging the PSU into the main lines is not needed and will not be any more grounded than just touching a metal chassis while building. Just an FYI.

Thanks for the advice you guys! I can't believe I forgot about grounding myself on the case its been a while my last PC build was when I was 13 so its been about 7 years since then! I'll box it up and take it home with me