Getting wet isn't a problem....as long as large long lasting puddles aren't forming. Deep Litter can handle quite a lot of water.
Agrees would be good to see it and have more info.
You may or may not need to remove the existing sand.
You'll have to assess the situation and surrounding area to decide if it needs to be removed or not.
First I would look at the drainage in the area.
Is it low ground?
Does water puddle there?
Are there way to divert any runoff from roofs and...
Lots of those wood chippings is a good base to start with......it'll 'eat up' just about anything else (especially the green stuff) you put in there without causing molding issues.
Just start putting deep litter materials over the sand.
This is used inside a coop but great description and video:
Here's a great description of contents and how to manage organic 'bedding' in a run or coop...and there's a great video of what it looks like...