If you are unable to find a particular Instrument on MetaTrader, you just need to select "Show all" in the Market Watch section.
Right-click on the Instrument section
Select Show All
If you are on a mobile phone:
To be able to add more instruments on a mobile device, you will need to click on the + icon on the top right-hand side of your screen as shown below.
You will then need to choose the appropriate category.
Then you will need to choose the instrument you want to see.