This is the REST API resource: 

https://www.hebcal.com/home/219/hebrew-date-converter-rest-api

What do you mean by "with Excel" ? 

My Excel chart has a series of dates that I would like to convert to their Hebrew counterpart. I would like detailed step by step guidance as to how to accomplish that goal. Thanks. 

I would like to determine the date in Column C from B. 

And this is not good enough ? 

https://www.hebcal.com/hebcal/?v=1&year=2018&month=4&s=on&maj=on&min=on&mod=on&mf=on&ss=on&nx=on&set=off

My; chart has a series of English dates. I would like to feed  the English date and retrieve the corresponding Hebrew date.I need detailed guidance for this as I  do not have developer training with Excel.  

Hi 

Ok so It seems that you will need to write a script to integrate with the hebcal rest API. 

It would be a bit out of the scope of this thread to try and  explain how to integrate with rest API's with no development skills. 

I recommend you seek a developer to do this job for you.