For more information please get the book Kundalini yoga by Swami Satyananda Saraswati. Another book I would recommend is the arousal of Kundalini by Ajit Mookherji

For more info on Bala Mantra:
https://www.manblunder.com/articlesview/bala-mantra

I'm following these Swamijis or gurus on YouTube You can watch their videos for information. For a guru assistance, you need one staying in your area. I have one guru that I met 20 years ago. He was guiding me for awhile before I moved to Singapore for work. I have lost his phone number. And I didn't keep in touch. And now I want bro embark on full Spiritual path. I read books by Swami Sivananda, Paramahansa, Sir John Woodroffe and many more. All of them shared similar research on Kundalini and the steps to live harmoniously with this energy.
Here are some lists of YouTube channel that I follow to gain some knowledge:

https://youtu.be/q0Yn_eU0FLE

https://youtu.be/ta5D28QpI74