Joining in here because you were asking about the climate adjustment thing in
your thread on the "Welcome" section of the forums too. I'm a newbie too, so what I'll say next is based on what other people have written when explaining things to me, or in things that have been said in other build threads, but I'm pretty sure it's right -- and I'm completely sure that someone will correct me if I've made any serious errors
I don't think you need to keep it in the box; the important thing is to not do too much work on it before the wood has adjusted to the climate that it is in now. Experts here on the forums have suggested to me that a week or so is about right.
Wood expands or contracts depending on the temperature and humidity. Your guitar was made (I think) in China, and at that time all of the pieces were a particular size and shape because it was a particular temperature and humidity there. Then it went to Australia, and sat in PBG's warehouse there, so everything expanded or contracted due to the new temperature and humidity. Then, it was put into the unheated cargo hold of a plane, and flown to Portugal, and probably adjusted a little during the flight. Next, it sat in whatever storage the Portuguese Customs kept it in for a week while that was all sorted out. Finally, it has arrived in your apartment.
The changes in size and shape are going to be really small -- millimetres or less, not centimetres or anything crazy like that. But because guitar parts have to fit together precisely, it's best to wait until the changes have happened before doing anything serious like sanding things or putting screws in.
For example, let's imagine that the heel of the neck -- the bit that goes into the body of the guitar -- was expanded when it arrived, but you tried to put it together right away without letting the wood adjust. You would try to fit the neck into the guitar body and find that it did not fit, because it was too large. So then you might use sandpaper to make the pocket in the body larger, to make it fit. Everything would look good, so then maybe you'd move on with your build.
But then, over the course of a week, the neck would shrink a little bit as it adjusted to the temperature and humidity in your apartment. When you tried to put the neck in, you'd find that it was now loose, because of the sanding that you did earlier. It would probably not be a disaster, and people on these forums would be able to suggest ways to fix it, but it would be an extra problem that you would have avoided if you had let it adjust to the local climate.
That's not to say that you can't do anything for a week -- for example, you could shape the headstock. That doesn't have to fit into anything, and a fraction of a millimetre here or there won't matter, so I don't think there would be any harm in doing that right away -- at least, I did mine only a few days after receiving the kit, and it doesn't seem to have done any harm...
I hope that helps!