Keyword mapping is process to target keyword on relevant page. Syntax to map keyword is easy and similar to syntax of checking indexing.
“Keyword site:sitename.com”. This syntax will show some results. Now you need to check those results closely. Only first result is considered appropriate for targeting or mapping keyword. If you think that this first result is not appropriate to map keyword, you can change it by internal linking. If you link your keyword with appropriate page of site internally, Google will definitely update its results within 5-6 days.
Keyword mapping is counted in initial steps of search engine optimization. In various SEO reports you can see that is taken while starting off page optimization.