Open your browser window and navigate to the WLED interface for your project. This will be the name you set  during software setup -- I called mine coffin.local so that's what I type into my browser to connect.

Be sure your device is on the same WiFi network you set up on your microcontroller.

Now it's time to play around and create animations that create the effect you want. I had the most success using a chase animation, slowed down considerably (use the slider at the bottom of the Effects tab to control the speed). The bottom slider will allow you to control the width of the bands. 

What we want here is for the first half of the strip to light up and then go dark, while the second half of the strip turns on. The animation speed and type can really make or break this illusion.

Watch some videos of the illusion "The Infinity Boxes" by TANZER to get some inspiration. Different light settings make this project feel vastly different. WLED gives you the tools to allow your own artistry to come through.

Once you're happy with your animation you can save it as a Preset, and if you tick the box labeled "Apply at Boot" then your animation will start up automatically. when you turn the project on.