Make it as easy as possible for users to go from general content to the more specific content they want on your site. Add navigation pages when it makes sense and effectively work these into your internal link structure. Make sure all of the pages on your site are reachable through links, and that they don't require an internal "search" functionality to be found. Link to related pages, where appropriate, to allow users to discover similar content.
And so on and so on. The point of this step isn't to come up with your final list of keyword phrases. You just want to end up with a brain dump of phrases you think potential customers might use to search for content related to that particular topic bucket. We'll narrow the lists down later in the process so you don't have something too unwieldy. Once you have your final list, there are several data-driven tools available to you for finding out which keywords you're most likely to rank well for.
QUOTE: “You always need textual content on-page, regardless of what other kinds of content you might have. If you’re a video-hosting site, you still need things like titles, headings, text, links, etc. The same goes for audio-hosting sites. Make it easy for search engines to understand your content & how it’s relevant to users, and they’ll be able to send you relevant traffic. If you make it hard for search engines to figure out what your pages are about, it would be normal for them to struggle to figure out how your site is relevant for users.” John Mueller, Google 2019
SEO is an acronym for "search engine optimization" or "search engine optimizer." Deciding to hire an SEO is a big decision that can potentially improve your site and save time, but you can also risk damage to your site and reputation. Make sure to research the potential advantages as well as the damage that an irresponsible SEO can do to your site. Many SEOs and other agencies and consultants provide useful services for website owners, including: