Good afternoon,
In response to your question, I'll give you your first lesson here. Your function calls at the end of your question are incorrect. Your initial function is a partial application:
const cons = (x,y) => f => f(x,y)
This means you need to first pass some x and y value to cons and then pass a function to that. You have it backwards in the code you posted. It would go like this:
const cons = (x,y) => f => f(x,y)
const pair = cons(5,3)
const car = (x,y) => x
const cdr = (x,y) => y
pair(car) // returns 5
pair(cdr // returns 3
As you'll notice, you have to pass functions to pair in order to complete the partial application.
I can give you more well explained lessons like this through whatever your preferred platform is.
I'm located in New York, currently. But I can be flexible with my availability. So whatever time works best for you can work for me as well.
I look forward to hearing more from you soon.
Best regards,
Naythan