Hi @noelflores ,
Following your "When item is created" trigger, add a "Get items" and use the filter query as @Expiscornovus advised. You would want to add in the time if you are looking to return anything within the last 24 hours. If it is anything for just today, then remove the time from the query.
Then as @Expiscornovus advised, you need to add a condition where you check the length of the Get items body value, if this is equal to 1, then you can trigger the email in the yes part of the condition.
What this will essentially do is to count the amount of records that exist within the timeframe that you filtered, if there is only 1 then this would be the first within that timeframe and will send an email. If there is more than 1 then it won't and won't trigger the email
