You usually need to carefully prize out the Alfa badge to reveal a cross head screw before it can be dis-mantled.
Once apart it should be fairly obvious where the pieces go. Leave the battery and battery tray to one side as they can be re-inserted later. Check that the circuit board has the open, lock and tailgate release buttons properly attached as sometimes the solder joints fracture if buttons are pushed too hard, if all OK lay the circuit board in the relevant half of ths casing. The spring loaded retractable key needs to be wound on the spring two revolutions to give it the strength to pop open correctly. Carefully put the two halves together and attach screw, cover with badge logo (small drop of superglue to retain) and then with key in open position re-fit battery tray and battery.