Plywood is the fastest, easiest material for amateur boatbuilding
because it comes pre-sanded and goes together in large pieces. The
more pices to a boat, the more work it is to build, generally.

The simplist shape is a long, low dory, ie two sides and a bottom. The
sides are angled out to give some curvature to the bottom, and more or
less curvature can be had by shaping the bottom edges of the side
pieces. A popluar form of this boat which can be built to carry two as
you suggest, and for which free plans can be found by searching the
Internet, is a "pirogue", a Louisiana swamp boat created by French
Canadians, or Cajuns, expelled from Nova Scotia by the British
government in 1755.

Plywood canoe plans tend to be more complex, each side made up of 2 or
more pieces, and reverse curves at the bows. They tend to need several
evenly-spaced temporary shapes (molds) set up to bend the pieces
around to get the right shape. They also usually call for trim pieces
along the gunwales and at the ends. Doable by beginners but time
consuming.

A long, low punt is another alternative but they are usually poled or
rowed instead of paddled.

Good luck.