There are seven locations of the principle chakras from lower end of spinal column to the crown of the head: Muladhara, Swadhisthana, Manipura, Anahata,Vishuddha, Ajan and Sahasrara. As the place to store subtle and vital energy forces, each chakra represents a state of consciousness with particular characters and corresponds to the seven lokas, astral or mental planes. The philosophy of chakras is very helpful when practising Yoga. I will focus on the following two chakras.
Muladhara locates at the lower end of the spinal column and represents the Earth principle, which bestows breath and mind control, and knowledge of past, present and future. Surya Bhedana Pranayma and Uddiyana Bandha can be the good examples to hold breath and lock Muladhara chakra to heat the body.
Swadhisthana locates at the genital organs and represents Water element, which confers psychic powers, intuitional knowledge and knowledge of astral entities. To practise Bhujangasana and Vamadevasana can strengthen the genital organs, as well as Swadhisthana chakra.
Meditation is a way of focusing your mind and stimulating body cells, as well as an agent to help us to reach chakras. As a particular posture, Padnasana is well known for its effectiveness to concentrate our attention on breathing, mind cleansing and soul pursuing.
There are various forms of meditation, Padnasasa is not necessary if you are not comfortable with the posture, you can sit anywhere with any posture and start to meditate by closing your eyes, controlling your breath and focusing on something. You can meditate by your own or with a group of people.
For better effect, do not meditate after meal. After shower will be an ideal time to relax and meditate.
There are two ways of nose cleansing: Jala Neti and Sutra Neti. The previous one is comparatively easy by pouring salt water into one nostril, then raises the head and blows the excess water out of the nostril; or, raises the head and allows salt water to flow down into the throat and out of the month. The latter one sounds difficult: insert the catheter into the nostril, and then draw it out through mouth slowly and carefully by using the index finger and thumb. I tried both and found they are very useful to treat my sinus.