Help With Trigger

Pls I have a requirement for below.

AFTER UPDATE OR INSERT OR DELETE OF IS_DEFAULT_SCHEMA ON IC_SCHEMA_CONSUMER

1. 1. Check whether the default schema is available for the consumer, if available
   1. a.       If the user is trying to update to a different schema as default, set the is_default_schema value to 2 for the current
   2. b.      If the user is trying to insert a new record with default schema value as 1, then set the is_default_schema value to 2 for the current , else nothing
   3. c.       If the user is trying to delete the record where is_default_schema value has been set to 1, throw the error.