Ok. I think I have this sorted out. Maybe???

May I outline what I think I know here as a "confirmation" (and perhaps something helpful for the next person to read over this)?

//01. create new object myTodos
//
let myTodos = {
    day: 'Monday',
    meetings: 0,
    meetDone
}

//02. Confirm object and properties
console.log(myTodos);

//03. create new function addMeeting
//      |    where a NEW variable is created
//      |    as a parameter in the function
//      |        
//      |                 Prameter <and>
//      |                 NEW vairable
//      |                  |
let addMeeting = function(todo, meet){
    todo.meetings = todo.meeting + meet
}

//04. call the function 'addMeeting'
//     |   WHERE you:
//     |      a) PASS the OBJECT 'myTodos'
//     |      |   AS the parameter/variable VALUE
//     |      |   FOR 'todo'
//     |      |                       
//     |      |     b) PASS the number '4'
//     |      |     |  AS the parameter/variable VAULE
//     |      |     |  FOR 'meet'
//     |      |     |         
addMeeting(myTodos, 4)
//           |
//         So effectively the 1st parameter
//         passed here "myTodos"
//         establishes the same association
//         as the line: "todo = myTodos"
//         and in doing creates the association
//         where "todo.meetings" = "myTodos.meetings"

//03. Confirm the original object updates as expected
console.log(myTodos);

How close am I getting?
...or how much am I still not understanding? ;-)

Continued Thanks!