It appears to be a tropical Island right...
And an Island is and Island. One of the first few things is to chose a direction of the beach and head out in that direaction for half the day, if there are people you are with, you retrace yoursteps back for the other half of the day, while you travel you try and assitaine three things.
1: How big is this Island, does it wrap around to meet itself, is it a full beach island (can't remember proper name, prob something like Reef Island) this is to say that it has beach on all sides of the island, never rising into cliff faces or such. If it does have cliff faces naturally you don't climb it and just return back to 'home' and report findings.
2: Discover if there is anything useful along the coast line, such as Palm Trees or Fruit Trees that grow along the side, if there is any kind of certain wood that can easily be cut/collected but still remains strong. And if there is any other resources, not as in Iron or Coal or anything like that, but things like flint or such where simple scavenging off these resources can bring forth different results.
and finally
3: If the Island is not a Reef Island, where does it show its highest area, where are there rivers leading to the ocean from the middle of the area and if there is any clearing or open stretches of land between the beach and the inland.
This can be done by two people, one heading one direction the other the other. Naturally.
The rest should be busy collecting large branches and leaves and anything that could be scavenged from any remains of the aircraft if it exists (can't remember after all this writing) and begin to construct a shelter near the edge of the beach, it is unknown how high the tied rises, to know you could look to the edge of the beach and see if the soil appears to erode away, if there are signs of that, the tide covers the WHOLE beach, and anything built of left on the sand will be lost in the night. Constructing a Shelter should be done a few meters in from the soil/beach joint and in a mostly large open space or against some stones if there are any. The first night day is mainly this...
Constructing Night Shelter,
Scouting along the beach. Traveling into the Island this early can lead to being lost really quickly. Most important thing to be looking for is something like a river or a simple spring.
Collecting simple food, such as Nuts and/or fruit from the nearby foliage. Any chances of meat or fish being collected this early is too much to regard...