I don't know what your goals for meditation are, so it's hard to answer these questions in a way that I think you will find satisfactory.
For some, the goal of meditation is not like the goal of, say, exercise is for many. That is, it's not something you do to get something as a result later or to build a lasting result as a consequence of something you do and forget.
Rather, it is a movement into a new way of relating to everything in the world.
Practice is not limited to something you do and then forget, although doing something and forgetting can certainly be practice.
This is one interpretation of "the path is one but the path is many."
Anything can be practice. Practice is simply being mindful, and meditation is one way to be mindful that can help you be mindful more often.
Some forms encourage various different kinds of meditation so that it becomes easier to follow the thread of it, to experience the similarities of mindfulness during different forms of activity... hence still and moving meditations and all sorts of other meditations.
Having a set time and place to meditate can be good. The end result can be that everything is practice, every activity is meditation.
