Beginner help needed for the STS-pi

My son and I are making the STS-pi together. Both of us are complete beginners and are stuck.

We have Rasberry pi 4 as well as the recommended Camera module, and the Explorer Hat. I think our pi4 has wifi so we can control it from our phone - so I don’t think we need the wi-fi dongle, though I’m not 100% sure about that.

We watched the Conner Plant Video to build the STS-pi chassis, which was easy to follow just the right level for us so we’re good there. We have a raspberry pi4 and have installed the software onto the SD card, and inserted into the raspberry pi. We can see the operating system on our monitor and our mouse and keyboard seem to work, so all good there, but that’s as far as we have got.

My son knows scratch, and we both know a bit of python. We were hoping there was an easy to follow video or instructions that will enable us to get the STS-pi roaming around, but we are completely stuck. Are there any beginner friendly videos that matches what we have bought and shows us how to get our STS-pi roaming around?

Any help appreciated. Thank you.