I'm new to the site, I have set 3 in the time box.
In the summary of the snipe it states 3 seconds, but in the advice box it mentions not to set less than 3 minutes.
Advice please, how to do this.

These are not the same things.
Your snipe must be set up and ready at least 3 minutes in advance. This way the service has enough time to prepare, login, check the listing and able to bid.
The snipe time can be set to any number of seconds. This is the actual time when your bid will be placed.