How to send an email automatically when values are met.

Hello,

Let me start with that I'm a rookie when it comes to VBA programming. I'm attempting to set up a code that will send an email automatically when certain values are met. To give more background, I'm building an inventory log, the purpose would be for when I enter a certain amount of supplies my cell would switch to "supplies low" and that would be the trigger for the email to be sent telling the person to order the supplies. I would also like to set it up to send it a few different triggers. So for example "Supplies Empty" would be another trigger phrase that I have one of the cells set up for.

I know how to set up VBA to send emails, but I don't understand how to set it up for automatically sending them based on certain triggers.

Thank you!