Enterprise Manager

Hello,

I've got a situation in my company.
A system based on Oracle 11g was installed here.
The database server works on a Windows Server 2008 64 bits.
The people who installed the system implemented a diary backup full with EXP command.
But this is not good for us. We'd like to have a backup full once a day and a backup log every 1 hour.
Our expertise is SQL databases. This is the first Oracle database system we have here.
The people who implemented the system will return only in November, and I need to implement a new backup routine. And we will take Oracle courses only in October.
By checking some documentations I saw that the first thing we need to do is to activate the archive log.
I confirmed in sqlplus that archive log is not activated here.
It seems that if I activate it, I will have new backup alternatives in Enterprise Manager screen.
I have access to the Enterprise Manager, and also to the sqlplus.
I'd like to know the steps I should follow in order to activate the archive log.
Could you please help me ?

Eduardo