The first thing you have to do is create and account. I know that there is a huge resistance to giving out personal info like your email address and phone number but the alerts have to be emailed to you. So we will need your email address. If you create an account your email address is your username. The site asks you for a phone number for your password. This is where we lose a lot of people. If you don't want to share your real phone number just make one up (555-666-7777).
Once you have an account you will be able to save searches and go back to them when you want. When you save a search, the system will automatically set up email alerts for any saved search. It's pretty obvious on the moblie how to save a search, but on a desktop or laptop it's a little less obvious. There, when you see the list of results for your search in the top left corner of the results list, there is a little green + next to a link "save search". Click on that to save the search. Then they system will ask daily? weekly? etc. That is regarding how often you want an email alert. If you have 5 saved searches, all set on daily delivery, you will get one email with links to the results of each different search. Name your saved searches, so you can navigate between the different searches. You can opt out at any time.
The email alerts include not only new listings, but also those that have gone under contract and the recent sales.