「客からの料理の注文が非常に多くて、大人気で流行っている店だ」と解釈した

As the two went through the entrance thinking 'We are hungry, let's have a feast here,' they found a strange notice on the back of the door: 'Our restaurant has many orders, so please be aware of that.' The two shrewdly interpreted this using their urban common sense, thinking 'This place must be very popular, a trendy restaurant with many food orders from customers,' and joyfully proceeded inside.