Hello ​@easefulessence ,
You can publish your automation at any time by clicking the "Publish" button in the upper right corner. However, it is important to make sure there are no errors. If there is a critical error, such as missing required information, ManyChat will alert you and prevent the publication.
There is no problem with building an automation, publishing it, and then, if you want to improve something later, making changes and publishing it again.

Below is a help article from ManyChat that provides a general explanation of how automations work:
https://help.manychat.com/hc/en-us/articles/14281166306332-How-to-build-a-Manychat-automation