Most... versus Most of the...

[Sakoos]

Hi sometimes I heard

1. What do most people do to earn for a living in Thailand?

2. Most rooms are fitted with a king size bed, but there are some rooms with 2 single beds.

In what sense is the word "Most" used with a noun and when can I use "Most of the ..." ?

[Yankee]

Hi sakoos

Most of the rooms refers to specific rooms.
Most rooms is very general.

"Most hotel rooms have a TV." (very general)

In this example, you first speak generally about the rooms in a specific hotel:

"We're going to stay at the newly renovated X Hotel. Most rooms there have a TV...."

And then speak specifically about certain rooms:

"... but most of the rooms in the older part of X Hotel don't have a TV."

Amy