How to create TNS and sqlnet

i don't login to database by toad, it is error as on ! i shown error, and file sqlnet+ listener+ tnsname as on! everyone can help me ! tks !

It looks like you installed Oracle XE on your local PC. If this is the database that you want to connect to, you don't need the other instant clients. You could just use the Oracle home that came with that database. In that case, you don't need a TNS_ADMIN variable, and your sqlnet.ora, tnsnames.ora, and listener.ora should be in the RDBMS\NETWORK\ADMIN folder under the XE home.