Hi kishor, there is a document with links to all you need to know about section access:
In very basic way load users with a field related with data that makes the reduction:
Load * Inline [
ACCESS, USERID, REDUCEFIELD
USER, DOMAIN\USER1, VALUE1
USER, DOMAIN\USER2, VALUE2
USER1 will see the data related with 'VALUE1' and has no acces to 'VALUE2' data.
Or are you asking about security rules to access the apps