Hellow @jyoti-thelight!
Thank you so much for your interest.
Here is the step-by-step guide on how to send your order.
1. Go to your steemit wallet
2. How many Facebook reactions you want? 1 reaction costs 0.001. So if you order 500 reactions, it cost around 0.5 sbd or steem (any of these two). Just send the amount and I will do the math. :)
3. What is your memo? Simply, the link or URL of your Facebook post.