We have 3 ways of adding Stocks/ETF to your watchlist.
1) The first method is via the "Get Quote" button at the top right of the site. You will see a text box, the "Get Quote" button and then a "+" button.
If you place a symbol in the box and press the "+" sign it will add the symbol to your watchlist. This will let you add one stock at a time into your watchlist.
2) If you search for a symbol with "Get Quote" you will have the stock dashboard. In this page, on the left, you can "Add to your watchlist"
3) The last method is more of a "trick" than a planned way to do it. We can use the Rating section with the multiple rating module to have up to 50 stocks in the rating box and then use the "one-click add to the watchlist" button to easily add them to your watchlist.
Have a look at this video on the "How to" of these to way to add them.