Mark four points on your fabric. Start your thread where it will later be covered by beads. Bring your needle up at the top right and thread on enough beads to take you to the top left point, crossing the centre. Take the the needle down at the top left.
Bring the needle up at the lower right point and thread on enough beads to take you to the central point.
Pass the needle through the central bead of the first strand, then pick up enough beads to take the needle to the lower left point to finish the cross.
Structure of stitch
Crosses are very useful and have many adaptions. They can be worked in a variety of bead combinations; over other stitches, sequins and beads for texture or worked corner to corner for a diamond trellis appearance.
Crosses have four legs. If the central bead is large enough, by placing the first two legs closely and the second pair symmetrically opposite, it is possible to use this stitch and add more legs between the two original pairs.
Various Authors, The Royal School of Needlework Book of Embroidery (2018)