chore: update build process and instructions

Author: bahmutov

README.md

@@ -155,6 +155,14 @@ All components are in [src](src) folder. All tests are in [cypress/integration](
 
 ## Development
 
+To get started with this repo, compile the plugin's code and the examples code
+
+```shell
+npm run transpile
+npm run build
+npm run cy:open
+```
+
 - run TypeScript compiler in watch mode with `npx tsc -w`
 - run Cypress with `npx cypress open` and select the spec you want to work with
 - edit `lib/index.ts` where all the magic happens

cypress/support/index.js

@@ -13,5 +13,7 @@
 // https://on.cypress.io/configuration
 // ***********************************************************
 
+// custom commands provided by this package, built from TypeScript code in "lib"
+// using "npm run transpile"
 import '../../dist'
 import '@percy/cypress'