breakfastPromise.then(val => console.log(val) ) Is this a shorthand version of a function inside a method?

So Traditional Funtion name ( ) { functionbody }
On one line looks like: name ( ) { function body }

AnonymousFunction: // will need to be appended to a variable or 'something' in order to call it. ( ) { functionbody }
On one line looks like: ( ) { function body } is the same as ( ) => { function body } an anonymous function that takes no parameters:

an anonymous function that takes two or more parameters: (param 1, param 2) { functionbody} is the same as (param 1, param 2) => {functionbody}

Here's where I lose it - an anonymous function that takes one parameter ( 1 param) { function body } is the same as..... myparam => { function body }

so, where does 'myparam' come from and what is it? A parameter masquerading as a variable?

Then we take a step farther and get: breakfastPromise.then (val => console.log (val) ) .then is a method that can take one or two parameters. The second param is optional. The first param is automatically handled as 'resolve'. Why is there a function inside the then method? Where are the ( ) for the parameters and where are the { } for the function body? Can someone write the breakfastPromise.then in long hand? Why couldn't one just write breakfastPromise.then(console.log(resolve)); ?