Hi Divya,
Are you quite sure that the libraries are installed and you have access on _SYS_AFL schema. If you don't have access to the schema, then it is very likely that you will not see it in the Modeler.
As per the documentation, can you please check if the following queries return any information.
SELECT * FROM "SYS"."AFL_AREAS" WHERE SCHEMA_NAME = '_SYS_AFL' AND AREA_NAME = 'AFLPAL'
SELECT * FROM "SYS"."AFL_PACKAGES" WHERE SCHEMA_NAME = '_SYS_AFL' AND AREA_NAME = 'AFLPAL'
SELECT * FROM "SYS"."AFL_FUNCTIONS" WHERE SCHEMA_NAME = '_SYS_AFL' AND AREA_NAME = 'AFLPAL'
Regards,
Ravi