I’m using the Mailchimp integration, but I can’t see the AddEvent Calendar Links app content block

To use the AddEvent Calendar Links app, you need to be using the New Builder. If the Apps option is not appearing when you attempt to add a content block while designing your Mailchimp email campaign, you are likely still using the Classic Builder. 

To switch to the New Builder, go to your Account page and then Details and click on "New Builder": "Account" -> "Details"

Please note this only applies to new campaigns that you create

Now that you are using the New Builder, you will see the Apps option when adding a content block. See below:

Click here for a video tutorial on how to use the AddEvent Calendar Links app for Mailchimp.