Tide Alert enables setting alerts for a) High tide events b) Low tide events and c) Custom tide events
First pick the tide station you want the alerts from the Alerts screen and then configure the events by turning on the 'Enable Alert' toggle.
Tide alert also supports custom alerts giving you maximum flexibility on when you want the alerts. You can setup a specific tide level when you need to be alerted at.
My alerts are configured but I don't get any alert notifications.
Please make sure the notification settings for tidealert app is turned on in system settings by following these instructions.
Your notifications settings should look like the image below.