You can't learn mindfulness just by reading a book or watching a video. In order to learn the skill of mindfulness, you have to do the practices.
Learning to meditate is really about how we bring mindfulness to into our daily life. It's about how we are relating to the world and how we can have a better relationship to what is happening in our life.
Learning to meditate is one of the most powerful and impactful things you can do for your own personal mental health and well-being.
When we are really just accepting the present moment as it is, this is mindfulness.
Mindfulness is more about something we're doing with our mind than something we're doing with our body.
You can practice meditation whether you are religious or an athiest.
Meditation is a directed attempt to control your thoughts and content of your mind and thereby to gain some peace and quit, or atleast to be able to better understand the contents of your brain.