They are never really gone just the physical body the spirit is always around.
Each person who can communicate with spirits/energies, do so in different ways i.e we're all not the same.
Most part, I receive pictures in my head like a photo or a film being played. I rarely see them as a manifestation in front of me (spirits choose who they show themselves to). I can also talk to them, it's a 50/50 between me and my guide, if I am finding it difficult to communicate, my guide will step in and help me.
Or I can feel an energy in my space (aura) and know that they are there; either they will talk to me or do this via pictures, it depends on the spirit or what I find easier.
By the time you're very relaxed and just seemed to know what needed to be done. It is amazing how in these types of issues meditation can help on controlling our fears.