Start with two LED's and decide which direction you will stitch. Bend the inside lead towards the second LED and solder it then repeat until you have a string of four LED's. Then repeat the entire process five times.
Now bend the leads of one set to the side and attach another set between the two bent leads. Repeat this until you have filled out the entire grid.
Note: Always check the polarity of the LED's you are soldering. This configuration creates five parallel blocks of four LED's in series.