I been trying to make a 3d anime style face with reference images( front, side, and back views ) but I used a plane for each view.
But it has all 4 sides of the face but there in 2d and don't connect.
How do I combine the faces into a 3d face?
You should start by watching a head modeling tutorial to get a better idea of how 3d modeling works.
As you position a vertex in front view,
you also need to go into side view and position the same vertex from the side
as you add more vertices you get a 3d shape, not flat planes.
There are several ways to create models, one is creating a polygon at a time, some prefer box modeling where you start with a box or sphere and shape the model as you subdivide it to get more detail, while others find sculpting more intuitive.