Excel VBA - Outlook / Room booked

Good evening,

I need a bit of help creating 1 or 2 macros.

In the attached file I would like to add a button which will run the following

1. that can validate if a room is already booked and highlight the row in red without sending the invite.
2. that can crosscheck if there is a conflict on your schedule and highlight the row in yellow and not send the invite

I apologize if this has already been discussed I'm trying to piece code from multiple forums.

Thank you