This video presents how to take lotus from a forearm balance headstand as a preparation for Karandvasana. If you find that you can't balance well enough to work with this video, I offer the same set of instructions using the wall in another video on my channel.
Remember to maintain a true vertical position over your foundation as you work on this move. Once you flip the first leg remember to lift up that knee and push it back in order to successfully flip the second leg to complete the position. Alternate the leg that you start with to facilitate symmetry between the two sides. Think of your forearms, shoulders, and upper back as the foundation more than your head. Press into your foundation and also lift vertically up out that foundation.