In PostgreSQL the system determines which table is meant by following a search path, which is a list of schemas to look in.
The first matching table in the search path is taken to be the one wanted, otherwise, if there is no match a error is raised, even if matching table names exist in other schemas in the database.
To show the current search path you can use the following command:
SHOW search_path;
And to put the new schema in the path, you could use:
SET search_path TO myschema;
Or if you want multiple schemas:
SET search_path TO myschema, public;
Reference: https://www.postgresql.org/docs/current/static/ddl-schemas.html