Thanks for everyone's comment! It's really heartwarming to receive all of yours encouragement and advice! We will definitely improve on the navigation and instructions. Here are a simple tutorial if you get lost in the game XD:
Day 1:
1. Wake up in the house and press [F] to collect the 4 items in the basket
2. Press [B] to open backpack and follow the direction on the bottom of the small boat model
3. Go to the boat and press [F] to drive, drive all the way to the right until you see a pink castle island
4. Investigate the fish bone, the rock and the top of the castle
5. Go the the left of the island and investigate the boat there, you will find a map!
6. Go home
Day2:
1. Look at the map, it tells you that tdy shd go to another island
2. Drive the boat to a green island (shd be all the way north from our home)
3. Interact with the deer, rabbit and fox
4. Interact with the raccoon, got no respond
5. Click the treasure box and collect the items there
6. Go Home!
Day3:
1. According to the map, go to the pink castle island again
2. Find a swan at the top of the castle
3. Press [B] open the backpack and press [E] to hold the apple
4. Give the apple to the swan, she will give you the rudder
5. Go Home!
Day 4:
1. According to the map and the swan, go to the green island again
2. Interact with the raccoon
3. Sit on the bench and wait for 15s
4. Collect the hammock
5. Go Home!
Day 5:
1. Drive your new boat!