Select the object you want to retopology, click Initialize of Bsurfaces, and at this time "Mesh of Bsurface" is empty If you have selected the object you want to retopology in the window of Mesh of Bsurface first, the object and retopology mesh will be integrated and become the same color. After doing Initialize, if BSurfaceMesh is displayed in Mesh of Bsurface, it is OK. If you can only select the edge of an object, can you change it by changing the selection mode at the top left of the screen? Shortcut keys can change vertices, edges and faces with 1, 2 and 3 on the keyboard It's a machine translation, so I'm sorry if it's not understood.