In the keyword box you only add the one primary keyword phrase. This allows SBI! tools to track that keyword. It sounds like you are talking about your home page as each page on your site will have its own primary keyword.
Within your content for each page you will, of course, use the primary keyword as recommended by Analyze It!, but you will also add similar keywords so they flow naturally within the content just as your primary keyword will. How many to add, just once or twice in a page? That will depend on when your content sounds forced when read aloud. Always keep it naturally. Sometimes that may mean you can only add one, other times you might add five ... it just depends
It is not a good idea to do a page for each similar keyword ... the reason being your content is likely to be a rewrite and closely duplicate the original page. Search engines, particularly Google, won't like it if you do that. Let search intent of the keywords and what appears in the top 10 spots in the search results help you determine search intent of a keyword so you know if it is a different or same topic to what you've put on your site already.
I hope this helps.