Please read the docs before asking questions to not waste other peoples time.
You will not even understand the answer if you don't.
As you can see the create table change has auto rollback.
That's one of your questions.
As for the other, the tag is the tag you created with tagDatabase
change
(http://www.liquibase.org/documentation/changes/tag_database.html) or
tag command in command line (http://www.liquibase.org/documentation/command_line.html).