First you need to stitch a grid of long straight stitches, and then anchor the joints with French Knots.
Stretch the fabric in a hoop.
Take the needle out from underneath one of the joints.
Make two (or more if you like) wraps on the needle.
Insert the tip of the needle on the other side of the joint,
tighten the thread into a knot and pull through.
You have now anchored the joint with a French Knot.
The tighter the tension, the better the knots sit.
Homework:
Work a net on these three samplers.