How do I create entities (like create table..) or define DB Schema

I am able to define nodes, labels and properties via Graph ArchitectQL. Is there a way to define schema like we create DB scripts before inserting data. All the examples in tutorial are like creating nodes with values.

Neo4J is schemeless by nature, so there is no way to setup up rigid schema in the database. Consequently, you have to properly design your own data model to ensure that system is flexible enought to fulfill all the requests. Even though, it's possible to introduce constraints and indexes, there is a dedicated chapter for that into documentation - https://neo4j.com/docs/getting-started/current/cypher-intro/schema/