Keyword research should always be based on the keywords of the competition in order to discover optimization potential and gaps in your own domain.
A competitor's domain can simply be entered into the Research Cloud search bar, for example, to analyze its organic ranking (Organic Search > Organic Rankings).
The analysis can be done as described in this article: Keyword Research Using Current Rankings.
You can also compare your domain directly with a competitor's domain. Once you have entered your domain in the Research Cloud, click the "Compare Domain" button in the top right corner.
Several suggestions will appear for your choice. Just click on one to start comparison. Or you can enter another desired domain.
You are on the domain comparison page. At the bottom of the page, there are lists of keywords, shared and unique keywords. In other words, those that you share with a competitor and those that only you/only a competitor belong to.
You should add your unique keywords to your project, as you can use them to achieve and further develop a beneficial competitive advantage.
The shared keywords are also helpful, as they can be used to determine which keywords you are already competing with and which you should particularly keep an eye on.
A competitor's unique keywords indicate gaps in their own content. These keywords are convenient for the Brief and adding to the project.
You can export the entire list and then upload it to your project (How does a keyword upload work?). In order to export, click on the three dots in the top right corner of the list and then click on "Export". Please note that export credits are charged for this, the amount of which vary by volume.
If you only want to add specific keywords from the list to your project, you can check the relevant keywords (in the box to the left of the keyword) and then click on the "Select Action" > "Add to project" field at the top of the list.