Field Updated based off Call Status

Field Updated based off Call Status

I'm trying to create a Field Update where:
When Call Status is Completed
Lead/Contact/Account Description field with the information in the "Outcome Of Outgoing Call" Description field.

Once our sales team finishes their calls and they add a description about the outcome of the call, I would like that call description to be add to the Lead/Contact/Accounts description field, with a meaningful timestamp, so we know what was discussed during the last phone call.

I have tried the Field Update option but that does not give me what I am looking for, the Instant Action option does not have an option to update  the Lead/Contact/Accounts description field.

I do not know how to code, so the Function option is not an option for me, unless someone can tell me what coding langauge I need to know, then maybe I can figure it out but that is not a good option for me.

Currently I have the Workflow set up as follows:
When Call call notes is modified
And
Call Status is Completed
Then
And this is where I am stuck becuase I cant see a way to set it up so that the Lead/Contact/Accounts description field is updated with a timestamp.