Alerts are an automatic current awareness service.
Typically you register for the service and then create a search strategy or personal profile which will be matched automatically against each update of the database. An email notification is sent to you on a regular basis. Try out a desired search and review the results. For a topical search a good practice is to do the search with a date limit of one year, and see if the number of search results is a reasonable amount to get in weekly or biweekly alerts. Broaden or narrow the search as needed.