Need a different size tray? You can adjust the dimensions by copying a fresh template from http://www.makercase.com/, just make sure it'll fit on the acrylic sheet you're cutting it from, and be sure it's an open-lid type box, rather than a fully enclosed one.
It may take multiple passes to get a clean cut on the Vector Cutting stage of Step 3; if you're not sure if it's cut all the way through, just run it again without moving the material from its position. (It's better to take more time and be certain of the cut than to move it prematurely and be stuck with scrap parts.)
http://openclipart.org is a good source for graphics to raster engrave into the box's sides or bottom surface; just be sure to match the Fill and Stroke settings and convert them to a path before attempting to cut.
Much of the advice from the Laser Cut Box project (found at https://www.makehaven.org/project/laser-cut-and-engraved-box) can be applied to this project.
Similar to the Laser Cut and Engraved Box project available elsewhere on this site, the Acrylic Dice Tray is an invaluable resource for tabletop and board game use--durable, highly customizable, and easy to make!
These instructions do assume basic proficiency with the Universal laser cutters, and general knowledge of the use of Inkscape for optional customization, but other than that this project is fairly straightforward, and is an ideal next project for those who have completed the laser cut box and want to branch out to new materials.