I'm at this point but I CANNOT click on the ladder to go down.
Is there something you need to do to make this happen/?

Walkway to cave: Let's look for the walkway shown on the picture in Drake's locked drawer. Go back down and exit the lighthouse. Now that we have seen the map in Drake's secret drawer, go around the hut and click behind the hut left of the wall with the emergency lighting.]]caz

You have to have seen the map that is located in the locked drawer at bottom of the bed in Drake's room.

From the walkthrough:

Drake's room:
Use the lantern on the picture on the wall right of the desk. Click on the tower above the cliff on the painting. Press the button and a drawer below the bed is opened.

A picture of the lighthouse with a purple 1, green 2, yellow 3 and blue 4 above a metal canister is seen. Another picture of a series of walkways going towards under the lighthouse is depicted. Note that the start of the walkway is behind the lighthouse and goes to a cave under the lighthouse.


If you have seen the ladder down but can't go down that ladder - move the cursor and see if you can get the down arrow.

Went back to it many times.
It's a GOG DL so don't know if it makes it buggy.
caz

Have you gone beyond this picture?

MaG this is where I am and I can go down the ladder

Good. Now that you can go down the ladder. Then turn away from the ladder and walk the walkway until you get to the caves.

Sorry.
I can't go down....

See that curved metal there close to the wall - bottom part.
There should be an active cursor there if you saw the map that is mentioned in the walkthrough.
Best to open that bottom drawer again and click on all the papers. There are several in there and you might have missed the map.
Once you did that you will get an active cursor here.

I don't have a saved game on this part anymore.