Hi @powersusers
If you want to send an email notification the next day, please use the method provided by @VJR .
Because timestamp needs to be filled in do until action, so please format the time as 'yyyy-MM-ddTHH:mmZ'.
'HH' refers to hour, 'mm' refers to minute.

Do until at 10 o'clock the next day.

If you want to send an email notification delay one day, you can use delay action directly.

Regarding your second question, because the trigger you used is when a new tweet is posted, Get response details is used together with When a new response is submitted trigger. So it will have an error.

Hope the content above may help you.
Best Regards