You have created a report that is set up properly with the correct filters and the correct options.  Make sure, for instance, that if you are wanting to know New Users created in the last month, that the report is set for Duration: Last Month and not a Custom filter.

An important note:  Each report can only have one schedule.  If a report needs to be run several times, with several different parameters, you have to create separate reports for each parameter.  

Use the report Tab/Object and the Search function to find the report you are looking for - you can also navigate to the folder.  Click on the link to open and run the report.  You'll find yoruself on the Report Details page with the data below it.  On the Run button of the Report Menu, click on the arrow to choose other option and choose "Schedule Future Runs."  A new window will open.

This would be important if the report had View options like "Only my Users" or "Only my Organization.'   But here you specify who the report should be run as  (which determines what data will appear in the report).  For a system admin or staff member -- it will report on ALL records per the filter.... but if you make the Running User one of your partner staff for example - it will only return data that they would see in their portal based on the records they have access to.

We suggest you use the Lookup magnifying glass to ensure you have spelled and spaced a User's name correctly.

Who do you want the report mailed to?

The "me" here is the you, the Logged in User.  You can confirm this when you choose the To me and/or other option.  With this option, you can choose to schedule to send this report to several different users.  This is an interface you should be pretty familiar with.  Use the Add and Remove button to define the recipient list.

By indicating the frequency, further choices appear in the box beside it.  If you so choose, you can have reports run on the first Monday of every month.  The frequency would be monthly and the additional parameter would read: On the 1st Monday of every month.

Do you need this report only during a certain campaign or is it something you will need continually?  Also, what time, on the day of the report  run, do you want to gather the data?  Its best to run it in the wee hours of the morning when the site isn't busy.

If you have made modifications to the report before you started the process to create an AutoRun, this is the option that will save your filters, options, and report layout.  This will overwrite the existing file.  If you choose "Discard report modifications" the scheduled report will revert back to the most recently saved file.  Now you can hit Save Report Schedule.

It's also possible to have reports automatically sent to some of your customer portal users, but to do this there are two things you need to do to make this happen:

You will notice now that a schedule icon appears next to the scheduled report.  You can hover over it to get information about the schedule.

To change or delete the schedule, run the report again, choose "Schedule Future Runs" from the Run Report button, and click on the Unschedule Report button or change the details of the scheduling.

Navigate using the schedule icon shown above to the Schedule Screen for a particular report.  One of the options is to unschedule a Report.  This delete all scheduling associated with this report.