There seems to be an issue with the attachments being processed so they get released. It is best to insert the images directly into your post. The create event action shows you the format that is needed for the action:
You will enter it in yyyy-MM-ddThh:mm:ss format and choose the time zone of the event. For example, if you wanted to create a meeting that starts at the current time three days from now, you would use this expression: addDays(utcNow(),3, 'yyyy-MM-ddThh:mm:ss')
For illustrative purposes only, the end date is four days from now: addDays(utcNow(),4, 'yyyy-MM-ddThh:mm:ss')
How you'll get the information using Microsoft Forms so it is in this format will be challenging since the date field does not include time information. If you're asking how to get the data in the ISO8601 format needed for this action, please show the format you are getting returned from your form response that includes the time information. You'll need to be sure the time format uses 24-hour and not 12-hour format. In 12-hour format, 01:00 could be 1 AM or 1 PM, which is why 24-hour format is needed so it returns 13:00 for 1 PM.