Never mind! I didn’t realize there was a button action type of custom Salesforce button! Thanks

Glad you figured it out.   If you don’t have the button set up in Salesforce, you could have simply made the button type “URL redirect” with the URL being “/apex/CarePlanMerge?id={{{PatientId}}}”   (This assumes that PatientId is in your model.  Also, not the triple braces…) 

Great! I’ll have that tool in my pocket for the next button. Thanks.