Plan your circuit...
Think about which inputs and outputs you need for your project. Look at the circuit designs under the exploringElectronics menu and use the same methods for connecting each of the inputs and outputs you will use.
Model the circuit using TinkerCad Circuits to see if it will work.
Build the circuit and casing/housing...
Once you are happy with your circuit design, build it on the breadboard with your electronics kit. Test that the code works when uploaded to the Arduino Uno board.
Next you'll build your casing or housing to 'package' your custom-designed product. The next page, assembleIt, shows you how to connect the electronic components securely so you can take them off the breadboard and insert them into the 'packaging' you have designed.