how to build the compass on the beach?

You need a cork, a knife, a needle, copper wire and a flashlight!
Use the knife to cut the cork. Get the batterie from the flashlight. Use the copper wire, the batterie and the needle on the tool. Now the needle is magnetic. Take the needle and put in on the slice of cork. Put that into the bucket full of water at the end of the jetty.

Use copper wire with wrench
Use battery with copper wire/wrench
Use needle with that
Use knife (opened) with cork
Float cork in bucket of water
Add magnetized needle to floating cork

Need the cork, the pocket knife, the soda, the copper wire, and the needle.

On your socket wrench use the copper wire and battery, then place the needle on it, this will magnetize the needle.

Once you find the knife and the soda, open the soda, then use it on the rusty knife. Use the knife to cut the cork. And place the needle on the cork

Place the compass in the water at the end of the dock