Sure, I can help you with that!

Here are the steps to create a macro that will open the URL in cell K16 when you click the button:

1. First, make sure the Developer tab is visible in Excel. If it's not, go to File Options Customize Ribbon and check the box next to Developer in the right-hand column.
2. Click on the Developer tab and then click on the Visual Basic button to open the Visual Basic Editor.
3. In the Visual Basic Editor, click on Insert Module to create a new module.
4. In the module, paste the following code:
   
   
   Formula:

   Sub OpenURL()
    Dim myURL As String
    myURL = Range("K16").Value
    ActiveWorkbook.FollowHyperlink myURL
End Sub 

5. Save the macro and close the Visual Basic Editor.
6. Go back to your Excel worksheet and right-click on the button you created. Click on Assign Macro.
7. In the Assign Macro dialog box, select the OpenURL macro and click OK.

Now, when you click the button, the OpenURL macro will run and open the URL in cell K16 in your default web browser.