Brick Joint-Bed Joint - This is the mortar joint that lies horizontally i.e the cement that sits on top and underneath bricks/blocks/stones.
To lay the bed joint you must tilt the trowel slightly and lay an even layer of cement along the line of bricks/blocks. Then make a shallow furrow and lay the next course.
Below is a 3D image that shows Brick Joint-Bed Joint. You can move the 3D object around with your mouse.