Redshift serverless

The first step is to create a new user who will have restricted access.

CREATE USER newuser PASSWORD 'password';

Next, you can create a new schema that this user will have access to

CREATE SCHEMA newschema;
GRANT USAGE ON SCHEMA newschema TO newuser;
GRANT SELECT ON TABLE newschema.newtable TO newuser;

Roles in Redshift are a way to manage privileges for groups of users.

CREATE GROUP newgroup;
ALTER GROUP newgroup ADD USER newuser;

Now you can grant privileges to the group, and all users in the group will have those privileges.

GRANT SELECT ON TABLE newschema.newtable TO GROUP newgroup;

You can refer the following link

https://docs.aws.amazon.com/redshift/latest/dg/c_redshift-sql.html