I said yummy but answer said should be tasty. I don't think there's a difference.
There is neither ח nor ך at the end of the word, hence there is no final 'kh' sound...
The tasty soup would be המרק הטעים. HaMarak HAta'im. Simple Hamarak ta'im is the soup is tasty.
if youre including the description as part of the definite article you add a letter hei to the description following the object.
There is only את in mid sentence not at the beginning, and only following an action.
You can think of את הבירה בבקשה as only the end of the sentence אני רוצה את הבירה בבקשה "I want the beer, please" - the "I want" is understood. If you wanted to order the tasty soup, you would say את המרק הטעים בבקשה