Liferafts typically have one entrance, with a rope ladder for ease of access. They are marked all round with the word 'Boarding' and an arrow to indicate the shortest distance to the ladder/entrance... that liferaft has most likely been washed off a ship, they're designed to inflate in contact with salt water/when a rip cord is pulled.
Aircraft liferafts have to be inflated manually, and for the most part are grey or yellow
they also tend to be rectangular as they double up as escape slides. Extra liferafts are carried on some aircraft on certain ETOPS routes. These are about 8'x3'x10", and require 4+ blokes to move (they weigh nearly 300kgs). They are usually kept in ceiling stowages or in overhead lockers. The reality is that no incident would ever see them used, as times when they would be suitable never happen