Lets assume you are standing naked on the shore of an
ocean in a remote and uncivilized place hundreds or
thousands of miles from people.
To build a boat you need two things. Tools and materials.
To build a furnace and smelt your own copper would
take months and you'll need all your time to find enough
food to eat so you will have to leave that for later.
So since there are lots or different kinds of rocks lying
right at your bare toes, you decide to use stone as a material
for the tool problem with the thought that when you get a little more
settled in, you will have time to think about using metal.
For materials your choice is limited to what you have. Wood, because
there are trees, and animals because there are no people, and grasses
and other vegetation,because..well..just because it's everywhere.
You make a spear from a stick and a rock and kill a seal, mabey three or
four. Then you skin them with another rock knife or mabey a clam
shell sharpened. Then you build a long skinny boat frame that is lashed
together from animal sinew and wood which you have found on the beach.
After a month and a half of trial and error,and trying to stay fed and
warm, VOILA! INSTANT BOAT!