OBIEE 12C or OAS file location is different than OBIEE 11G.
Below are the location for some critical files/logs/scripts.
NQSConfig.INI:
$/Middleware/Domain_Home/bi/config/fmwconfig/biconfig/OBIS
instanceconfig.xml
$/Middleware/Domain_Home/bi/config/fmwconfig/biconfig/OBIPS
Live RPD:
$/Middleware/Domain_Home/bi/bidata/service_instances/ssi/metadata/datamodel/customizations
Catalog:
$/Middleware/Domain_Home/bi/bidata/service_instances/ssi/metadata/content/catalog
Admin Server Log file:
$/Middleware/Domain_Home/bi/servers/AdminServer/logs
BI Server Log File:
$/Middleware/Domain_Home/bi/servers/bi_server1/logs
BI Tools (datamodel.sh, start.sh, stop.sh, status.sh, etc.. )
$/Middleware/Domain_Home/bi/bitools/bin
happy Learning !!