PL/SQL start

im fairly new to Oracle and PL/SQL but not with SQL..my question
what application will i type my commands in PL/SQL? i tried to use sql plus but it doesnt work..

I don't quite understand your question.

You can enter pl/sql commands using sql*plus.

select count(*) from user_tables;

You can save commands in a text file ( filename.sql ) and excute them:

@myprog.sql

I suggest you download the documentation for sql*plus from Oracle as well as buy a book or two.

You load PL/SQL programs via the SQLPlus interface. You can run an anonymous pl/sql program by doing the following:

set serveroutput on;
Declare
--Variable Declarations
count NUMBER := 1;
BEGIN
dbms_output.put_line(count);
END;

You can create procedures/functions by:

set serveroutput on;
create or replace procedure Test(count in number)
as
begin
dbms_output.put_line(count);
end;