I thought that when I added a board to watch board, it was automatically added to the watchlist. Isn't this what happens?
When you visit the watch board,you get this info: Quote
Adding a board to this list will cause all new topics posted there to be added to your watchlist automatically. You must enter the board ID, which is visible in the URL: https://bitcointalk.org/index.php?board=39.0.
However,you don't need necessarily need to watch a board for adding topics in your watchlist.
When you visit a thread,you can watch that thread by adding it to your watchlist by clicking the watch button on the top right corner of the page:
Or when you reply,you can explore the additional options below your text editor and check the watch topic option on/off:
