Place two blocks of the wood side by side.
Lay the exposed tang of the knife -- the metal extension of the blade that will go into the handle -- against the middle of the top plane of one of the blocks of wood and trace the shape with a pencil. Trace the shape again in the same spot on the other block of wood.
Use a chisel to remove the outline of the penciled areas on both blocks. You should remove enough wood to cover half of the exposed knife tang.
Cover the top planes of the wood blocks with a thick layer of epoxy glue. Place the exposed tang of the knife in one of the indentations and put the other block directly on top so that the indentations align.
Clamp the blocks and allow the glue to dry for 12 hours.
Shape the blocks around the tang using a rough file to create the general dimensions of the knife handle you wish to make. Be sure to leave enough wood so it will be at least 1 inch longer than the tang.
Go over the handle again with a smooth file or sandpaper to complete the design you chose, to soften any hard tips left by the rough file and to make the handle smooth.
Apply a wood oil to the handle using a soft cloth to polish it and give a finish. Wipe away excess oil with another soft cloth and allow to dry for the length of time indicated by the directions that came with the oil.