There are two major operations insert and delete. Insert is used to enter values into the queue while delete is used remove elements from the queue. The queue has a FIFO system, i.e. First In First Out system.
The queue is usually an array and has a limit and if you enter values greater than the limit then you should give an error message as overflow condition and if you try to delete elements from an empty queue you should give an error message as underflow condition. Please see the video for more details