One could start right away and experiment with a two minute meditation by staying in FGCB. Read the following article to learn this.
What are some breathing exercises for beginners who struggle with focusing on their breath while meditating?
https://www.quora.com/profile/Selvan-Srinivasan-4/https-www-quora-com-What-are-some-breathing-exercises-for-beginners-who-struggle-with-focusing-on-their-breath-while-m?ch=15&oid=83860240&share=b397af8e&srid=hNhWpw&target_type=post
My website provides all the resources for a most effective practice.https://awarenessjourney.org/