As I am not too confident in my skills, will it be possible to simply DL data, copy it on a SD card, plug it in a RasPi, plug power & ethernet cable = everything working?

Also will there be a time window for the original distribution?
I have no Raspi for now, and doubt I will have one in my hand in 2 weeks.
Maybe a month?

Some precision to not miss the 1st early adopter window would be great.