It's quite simple really. 

We are part of this conciousness or God, 
and we have materialized into this body.

We are still connected to this conciousness
but have a hard time finding our way back. 

Dream is the doorway to practice this union. 

Here is my plan of action for eternal life: 

First you have to accept that you are not 
the body, that you are not the mind, but 
that you are part of this 'conciousness' 
which is everything. You don't need to 
accept that fully, but having a healthy doubt
about what reality is, is a good start. 

Then you practice your dream.

If you don't remember your dream, you can 
start writing or talking about your dream. 

When there are more dreams coming, continue
to write about them until you dream regularly. 

Once you are there, start practicing lucid dreaming. 
Remember all day long 'this is just a dream' and
at one point during your dream you might say to 
yourself, 'this is just a dream' at which point
you will have the ability to start being aware 
in your dream. 

You can play with that new skill of lucid dream, 
but the next step is to move to an out of body 
experience. 

A simple way to go about this is to dream in your
dream. Lay down in your dream and fall asleep. Then
when you wake up from that dream in the dream, 
have the goal to wake up in your 'normal' life. 

That will bring you directly to a out of body experience.
It's hard to navigate at first, but it will give you 
a taste of what it feels like. 

You don't need to go all the way there for 
an obe (out of body experience) but it's somehow
a simpler way. 

The next step is to stay aware during the moment 
that you fall asleep. The mind can be aware, while 
the body sleep. At that time it's simple to slip 
out of the body. 

Once you have matered the OBE, well you are ready. 
You can then leave you body at will, to learn and 
to teach, and at the moment of your death you can 
then decide if you continue that path, or get 
re-incarnated or disolve completely in conciousness.