Question regarding PCB architecture

[FreshmanNewbie]

I am just starting to understand the EVSE architecture and how it will be on the PCB.

Hence, I went through this teardown video to understand the PCB architecture.

(I saw that in some questions, sharing videos is not recommended. But I searched on Google to find answers. But failed. Hence asking here).
My objective is to:

1. Understand how the main AC wires that are coming as input to the PCB, are getting converted into traces on the PCB?

Like, the input AC wire is incoming to the PCB. And output AC power wires is taken from different wires. Since there's no direct wire between input and output, the AC input is converted into some signal traces and then it is processed and then given to the output wires. But my question is where should the input wires end in the PCB and from where should the output power traces get converter into the output power wires? I see some terminal screws on the PCB. But from which peripheral or places should the traces come so that the traces get changed to wires?

1. Since we have high voltage (AC mains input) and low voltage (MCU peripherals), should any from of separate ground isolation is required? If so, can somene tell me which peripherals should have the AC mains ground and which peripherals should have the digital low voltage ground and which would be the ideal location to connect these two grounds together?

I apologize to ask two questions in a single question. But I feel these two are related and hence asking. Please help to understand this.
Thank you.

 

[FvM]

Analysis starts with a meaningful schematic, I presume.
Some important parameters for the design:
- current rating
- required isolation, is the low voltage circuit (if any) externally exposed and needs to comply with safety standards