We caught the train after checking out of our Brussels hotel. It was an easy walk to the station from the hotel and we had purchased tickets the day before.
The train station in Amsterdam is downtown, and we found the correct commuter train (more of a light rail with overhead power lines) fairly easily and in about 10 minutes were at the hotel.
We found the door under our hotel name sign, got buzzed in and climbed two flights of stairs to check in.
So many European hotels are actually in the upper floors of unsuspecting buildings containing restaurants, shops and bars, etc. on the ground floors.
Saw the Anne Frank House Museum, which was very moving.