Five Years After the Beginning, I Came Back with the Battleship

At the beginning, he travels to a planet that is 99% water. There is only one escape cabin and one workbench. Let's see how he survives on the desolate planet and develops technology step by step to return to the earth. When he returned to Earth, he found that it was not the Earth he remembered. What will he do? What will he do when he discovers that humans are not the only ones in the universe? This novel and its characters are purely fictitious. Any similarity is purely coincidental and should not be imitated.