It really depends on the nature of the problem and what you are trying to achieve.
Assuming you want two monitors to act as a continuous desktop ensure that both monitors are switch on before the PC. Navigate to 'System > Display' and select 'Extend these displays'. You can also drag displays here to rearrange them. It maybe that the one of the displays has not been recognized in which case you would hit the 'Identify' button.
A right click on the Taskbar will allow you to enter the 'Taskbar settings'. Here there should be an option for multiple monitors that will allow you turn off the taskbar on your second monitor.
So far the only issues I have is when I use my laptop in my dock and then disconnect it, some windows still want to open in the disconnected monitor and open off-screen and I always forget the hotkey to switch them around.
My USB-C docking station really comes in handy for this. I would recommend going ahead and buying that to anyone that primarily uses their computer at a desk.