The Console Window can be opened using any of the following keybind: Tilde ~, F8 F8, F10 F10.
You can cycle through hidden/minimal/extended state by pressing the said keybind again.
Image: Console Window in extended state
Console Window Bug
There is a known bug where opening the Console Window will break mouse input. Some people with access to debug build (Dev, Alpha testers, QA, etc.) which have access to the console is also experiencing the same issue.
It is planned that we fix it by rendering our own window in an upcoming mod.