"Qi is the energy of the heavens and earth. It is as real as the sun and soil. Perhaps more real, even, as it suffuses everything, even if in minute amounts, and can fundamentally change all it touches. Qi has many aspects and distinctions... It's a category of energy, not a specific kind. It's like saying 'plants'. Do you mean trees? Shrubs? <Algae?>? Crops? <???>?"
So, we have qi, the spiritual energy that underpins the world and the basis of all cultivation. Spiritual qi is the loose and free energy floating in the world, air and water and stone. Spirit stones are dense concentrations of spiritual qi. Bodily qi, sometimes called essence, is the energy that strengthens flesh and bone. Dragon qi is the energy tied to the fate of a nation, and 'true' qi is the spiritual mass of a person, the thing that your cultivation itself is made of. There are surely more types I don't know.
Qi perfects things. It makes them more. Depending on your perspective... Death qi could 'perfect' a person by killing them. That is more of the nature of death qi after all. All qi can be neutral or aspected, showing properties aligned with its aspect. The most common aspects are yin, yang, fire, earth, metal, water, and wood. But there are many, almost anything you can imagine. Blood qi is a derivation of water, perhaps with some influence of fire...
Cultivation, at your and my level, is the process of taking in spiritual qi, growing your true qi, and becoming more 'perfect'. It's a long, long road, and there are many mysteries I don't yet know. But the first step is to meditate and focus, learning to detect and then influence free spiritual qi. Then, using specific methods and patterns, to bring spiritual qi into yourself, and move it in cycles. These cycles change your body and spirit, making you stronger and faster and better at qi control, and over time will improve your true qi.
That is the first stage in a few words: Qi Gathering. The further stages are Foundation Building, Core Formation, Domain Establishing, Nascent Soul, and then... Several more, no doubt. I don't know the details. The truly immense can eventually become Tribulation Immortals. With varied and exotic methods to actually cultivate... And there are alternate paths to growing stronger. This is the 'standard' path that most humans use..."