Watchlist is a great way to track companies you are interested in. This contains only the list of ticker symbols you would want to monitor and analyze.
A Holdings portfolio can easily track the companies in your portfolio similar to a Watchlist but with a corresponding number of shares for each.
Transactions portfolio is the best and most powerful way to track and analyze your portfolio performance. It includes detailed buy/sell transactions in your account.
Summary of data required when creating Portfolio:
For Portfolio video tutorials, you can check them out here.