Korean for travel in Korea
You do not need grammar for a week in Seoul. You need about fifteen sentences, and most of them are three words long. Here they are in the order you will need them.
The first hour
Said to you before you say anything. Learn to recognise them, not to produce them.
Getting someone's attention
Korean does not use waiter or miss. You say this one word and someone turns round.
Eating
Side dishes are refilled free, which surprises people. And ask about the spice before you order, not after.
Finding things
Korean puts the thing first and the question word after - the reverse of English. Swap the noun and the sentence still works.
When it goes wrong
The two sentences that get people to slow down instead of switching to English.
If you only memorise three, make them 저기요 (getting attention), 주세요 (asking for anything) and 얼마예요 (how much). Those three plus pointing will carry you through a week.