Not enough information I'm afraid. It depends on which task and also the structure of your solution. If you provide more info you'll likely get a lot of help from this forum.
I just want it to send me a reminder that I should go in and look at the record on a particular date. So for example I could set it to send me a reminder on 20th Oct that I should go in and look at this record on that date. It should flash up the message when I open the database. Is it possible to do this?
You can have a start-script running 'on first window open'
- have a table (for example) with the reminders
- the starter script checks for reminders, for example by searching the reminder table for date_reminder = current date
- if there are records: Create a PopOver (pops up via script, semitransparent, in the Upper right corner (like 'growl', etc) with that data
- create a second field in the reminder table with 'done' to make sure that a reminder will only pop up until 'done'
You can have the start-script showing all reminders for the current week, current day, month - etc
If the file is hosted from FileMaker server, you can use an SMTP mail server and a schedule to run such a script once a day whether it is opened or not.
There are also other options that do this on a regular schedule via Install OnTimerScript and robot files opened on a schedule via an OS based scheduler such as "windows scheduled tasks".