Oracle fail safe are done on clusters.
One install oracle on both nodes on the clusters.Install oracle fail safe on both the nodes.You need to reboot the server after each installation.Pls read the installation manuals.First you have install the oracle,oracle fail safe .
After that you have to create the database using the oracle fail safe only.You should not create the database as you do normally.
All you need is only the parameter file only.
The oracle fail safe will take the job of creating the database,updating the tnsnames.ora ,listerner etc.
If you have any problems there is a option called verify databases.
Oracle fail safe will try to run the databases in both the nodes.
if anything is wrong you will get error message.
all your datafiles,controlfiles,logfiles should be there in the shared drives of both the nodes.
It is always good to start and shutdown your database with oracle fail safe .
keep a copy of tnsnames.ora and listerner.ora in a seperate floppy and have it in the disk also an additional copy.