If you read the previous article on the sandbox internals , you already know that there is a local playground, what it is made of, and roughly what it can do. What that article did not cover is how to actually play. This one does. We will build a custom certificate template for a fictional institution called Building Block Academy , simulate issuing certificates in bulk for fictional students on the local devnet, evaluate the on-chain costs, and inspect the final issued certificates in the UI. At the end, we will submit the finished template to the public UVerify UI repository so anyone can see Building Block Academy 's student certificates at app.uverify.io .…