This is not an original game. I just turned it into a word document and tried to make it easier for my students to understand.
The original can be found here: https://www.teach-this.com/images/resources/island-adventure-2.pdf
In order to save paper, I only print out one copy of the worksheet per group and one copy of the challenge cards per class. The only preparation you need is to print and cut out the challenge cards. These need to be handed out at random so you can do what I did and fanned them out like a card trick and asked them to "pick one" or you can prepare a bag or something for them to pull the cards out of.
First part is just explaining to them the scenario. Split the class into groups or "boats". Their boat is sinking and that they see an island off in the distance. They need to take 3 items with them to the deserted island and survive for 10 days until help arrives. I normally tell my kids to hurry because the boat is sinking fast. I give them 5 minutes to choose 3 items and to write why. The "why" part can take some time. You can either give them extra time for this part OR do what I did and tell them if they cant explain their reason in English, that Japanese is okay too. Since the reason isn't the main focus of the grammar point.
The second part is where it gets fun. Distribute the challenge cards randomly, 1 per group. Each card contains details for each island that the groups have taken refuge on. Some of the islands are bizarre so double check if you want to remove some of the cards. Some schools are stricter with violence than others. The challenge cards have some hard words for the kids so definitely walk around and help the groups understand. It may help to explain the islands to your JTE so that they can also help explain to the groups. Now the students need to try and explain how they are going to use their three items to survive now that they know about what kind of island they landed on. These kids get really have a great imagination so their answers are really entertaining to read so I love doing this activity every year lol.
The last part is optional. There is a little part at the end where they decide whether or not they will survive 10 days on their island. This year I tried having them present, and have the class vote whether or not the group would survive. This only worked well for me because my JTE's English is really good so he was able to clearly explain the islands to everyone quickly. I would suggest relying on your JTE for explaining the difficult stuff.