Let's say you already have a project set up on your Dashboard. Here's how to add new keywords that you wish to track on top of those you may have added earlier.
Within the Rank Tracker Dashboard, click on "Keywords" from the target project.
Here within Rank Tracker, you will be able to see your current tracked keywords and their respective ranking position, search volume, search traffic, keyword difficulty, SERP features, the URL and the date last checked. Within the mobile view, you'll also be able to see the respective mobile related data. [Subscription provisions: Only Advanced and Agency can see mobile rank and mobile difficulty data.]
Click "Add Keywords".
Add additional location(s) if needed (by default locations you are already tracking your keywords for will be shown here), then select or key in your keywords whilst separating each keyword with a comma. Then click "Add keywords".
Depending on whether your total tracked keywords exceeds your current subscription limits (find out how are tracked keywords calculated for Rank Tracker), adding keywords/locations will be disabled.