Сan't change the shape of the shader for a custom health bar

Hello everyone, I would like to ask for help in resolving this issue. I recently bought a set of resource shaders. Every day I can’t change the shape of the shader from rectangular to round, I looked through all the lessons on the Internet on this topic, but I couldn’t find anything. Maybe you have a guide on how to do this and how to tie the decrease and increase of health to this animation. I will be very grateful to you!