Before building a website or setting up a digital marketing campaign one should always start with keyword research.
Keyword research identifies the keywords and keyphrases people use when searching the internet for information, products and/or services.
By using tools like the Ubersuggest you can determine the number of monthly searches for a certain keyword or keyphrase. With that you know the potential number of visitors you can have on your website from a certain keyword / keyphrase.
If you combine this with the competition each keyword has (other websites that rank for these keywords / keyphrases) you can determine which keywords / keyphrases you should use on your website to rank high easily.