they are amateur builders, that is for sure. but they built it
according to the design God gave them. so i presume God helped them
with gathering of the materials also.
and since God created the animals, he has a way of coordinating the
animals on the ark.
by saying all these, i am, of cos, assuming that is you believed
there was a huge flood, and that there was an ark, then God must
have existed. if you believed otherwise, then sorry, i will not be
entertaining you.