If you are logged in to your Wi-Q account, your order history is available by opening the sidebar and clicking "Order History".
If you are not logged in, or are yet to create an account, you can do both things from the sidebar, under "Login" and "Register" respectively.
If your order has not arrived in the time you would have reasonably expected it to, you should call a waiter to inform them. You can do this by pressing "Call a Waiter" from either the sidebar menu or the menu at the foot of the screen, and entering your table number. Alternatively if a waiter is nearby it may be preferable to wave to them to get their attention.