Cannot connect external monitor to laptop

I have broken the internal monitor to my laptop and am trying to use an
external monitor. However, the current internal monitor is completely
broken and I cannot view anything on it. The computer opens up with
the windows page, however, the desktop does not appear. I have
messed around with the function keys, however, there is no
correspondence to the external monitor. The problem might be that I
have a Toshiba computer which I purchased in the US and have a LG
monitor that I purchased in Europe. I am not sure what to do
considering I have no visibility on my laptop and the Function keys are
not working as well. Any suggestions?