Alarm related query

hey i am currently working on a app in which i want alarm with a default ringtone set by me and dates and time are also select by me and user also as it depends on user he want default timning or user define and i also want to set the date of the alarm also and also i want to add a feature so that i can send user a message on their phone plz help …

you might want to try the alarm extension and settings extension
See also Q2 here App Inventor Extensions: Alarm | Pura Vida Apps