Back in the 90s celestion put together a comprehensive guide to designing and building your own cabinet the cabinet handbook.
Build your own 4x12 guitar cabinet.
Primarily the cabinet is a convenient way of housing the speaker so it should be solidly built to ensure no joint vibration unpleasant buzzing and be strong.
As guitar speakers are different so their cabinets are different.
The box design is acoustically less critical than that for hi fi or pa systems but proper construction is essential.
Draw circles for the speakers on the front panel of the cabinet with a compass or large protractor.