To answer the first and second question, you feeling so thing. Some say they feel thing worm, tickling feel or just a present. You can see it if you practice move chi in you eye( hence those how can see aura).
But in the beginning, just relax your body a mind so the chi can flow natural path ways. The 3 path way your chi
can flow but most common is the Fire Path. Basically your main chi flow move around your body from the center and sexual organs area, moving up between the skin and your spin, around the skull, moving down to your chest, and back to you center area again.
At that time, your chi is hitting your 7 Chakras/3 Dan
Tien, internal organs, and your outer body part like arms and legs(yes, they have their own flow.). Focuse on be aware of this flow will make understand other flows inside and outside your body.
Now the last question. Chi kung and qi gong are special
practices that deal with self-awarenss and chi flow. Qi gong is more External practice like building chi to your fist to do a powerful punch or sending chi to heal/kill someone, and Chi kung is more internal speeding your healing ability, prolonging health, and increasing natural ability.
Both are different but very powerful and both have the same goals; prolong life and self-awareness. They can also help with increasing psychic abilities, enhance magical powers, and reach immortality.