If this is your first resin printer, treat setup differently from any FDM machine you have used before. The Mono 4 works with liquid photopolymer resin, not solid filament, so the unboxing and first startup carry a different set of precautions from day one.
Unpack on a flat, rigid surface with room for the lid to open fully and space to work on both sides of the machine. Keep the printer away from direct sunlight and windows. Resin cures under UV light, and stray daylight can start hardening it in the vat before you are ready to print. Remove foam and tape carefully, and handle the vat and the exposed LCD screen with care. Both scratch easily and are expensive to replace.
Before touching the vat, resin bottle or build plate, put on nitrile gloves and safety glasses. This should become routine before every session involving resin, not just setup.
Seat the resin vat into its tray and check the FEP film on its underside for stretch marks, dents or debris from packing material. Keep tools and sharp objects away from it. Install the build plate and secure its clamp so it sits parallel to the vat.
Power on the printer, connect it to Wi-Fi if prompted, and run the on-screen startup routine. Anycubic’s leveling guide for the Photon Mono 4 covers the platform leveling step in detail. Follow it exactly instead of skipping ahead to a test print.
Setup is finished once the plate is leveled, the vat is clean and correctly seated, the room has decent airflow, and gloves and glasses are within reach for every future step involving resin.
Once the printer is level and ready, move on to the first print walkthrough to see the whole resin workflow in practice. If you are coming from an FDM machine, the FDM vs resin comparison is worth a quick read, since several habits from filament printing do not carry over to resin.