How to adjust the opacity of WaterBodyOcean

I’m using WaterBodyOcean to create underwater city, but underwater is too dark. How can I make it more transparent?

If you show some screenshots of the material I could be more precise. But taking a stab in the dark… Open the material that is used for the underwater and adjust the Opacity in the material graph. 0 is transparent and 1 is opaque, you can adjust it to any value in between. There may be some other cleverer techniques at work where you would need to adjust other elements but without seeing the Material graph it would only be speculation.