In my case, select all faces of cone except the bottom face, and inset them to create mid-line of conical surface.
and select that mid-line with edge loop select, resize them to match with radius of bottom circle. that’s how i made low column part of objective-cone primitive.
about to make top column part : i select top vertex of cone and bevel that with vertex-bevel (press V while bevel adjust) and i can make flat face on cone as if i slice top of cone horizontally.
so i extrude that flat face to make column part of top.
and as you know, rest part : make crevice form on primitives is just simple if you watch and follow well all of these videos in course.
