2. Blender Setup
2.A: Setting up the plugin
2.B: Preferred primary mouse button
2.C: Setting up important hotkeys
2.D: Making sure 'Walk' Navigation is set rather than 'Fly'
Setting up the plugin
Next, the normal and easy way to install Blender plugins is through the preferences interface within Blender, under the addons category; but if I recall there were numerous people who mentioned to me that this specific plugin wasn't being loaded when selecting the downloaded plugins .zip file from that menu, so we will have to put the contents of the .zip into your blender addons directory manually just to make sure. Make sure Blender is closed for a moment before doing this.
As I'm using windows (10), the folder found directly inside the .zip would go here.
For you, this directory will have a different address based on what your user account name would be on your PC, which is why I deleted my name on the image to prevent confusion. If your system username happens to be Montgomery for an example, the address would be -
Next, open Blender and click outside of the splash screen to make it disappear. The first thing we'll do is go to Edit > Preferences on the menu bar.
When the preferences window appears, click the 'add-ons' tab on the left, then scroll down to where the plugin you installed shows up (it will be in alphabetical order), you're looking for Import-Export: Unreal .t3d exporter, and make sure this plugin is enabled by setting the 'tick' to the left of the plugin title.
Now, before closing the preferences window, make sure you save your changes to your preferences by clicking the 3 small horizontal bars at the bottom left of the window then clicking Save Preferences.
Preferred primary mouse button
The neat thing about Blender is that you can essentially assign almost any function a hotkey or combination of keys. The one most crucial and immediate hotkey I will recommend setting up is free look navigation with WASD to move around basically the same thing as noclipping in an FPS, which Blender calls Walk Navigation for some reason. There is also Fly Navigation too but this feels like trying to manoeuvre a spaceship, so we're better off with Walk Navigation. The default kind of view navigation which Blender uses is some weird camera orbit navigation which is very awkward for 3d environments, but perhaps a lot more useful for modelling single assets/characters etc (even though I still use Walk Navigation to model assets too).
Before we do that though, just take note of the top of the keymap tab.
Note if you have another version of Blender installed:
If you configured some different controls, you have the option to import those settings from another version (importing the settings from newer versions of Blender might not work completely, but older to newer definitely does). if you wish to do this, first you will need to export your preset configuration from that version and then import the .py file you exported on the version you intend to use said presets. On the screenshot below, this is item 1.
(Optional but important):
Next, I would recommend making sure that you're happy with your primary mouse button. By default, this is set to right mouse button, I personally prefer to use the Left mouse button for most things, changing it to the Right I've found is only really useful when rigging an animated model that requires the left button free to weight paint (which is a separate thing entirely, as this tutorial focuses on BSP geometry). On the screenshot below, this is item 2.
Setting up important hotkeys
Now, we want to go onto where the controls are assigned, mainly the button to define Walk Navigation. Below in the preferences window with the Keymap tab selected are where the control scheme is located, and this interface is sectioned out into almost a directory tree. To find where Walk Navigation is assigned, expand 3d View > 3d View (Global) and if scrolling down you should notice View Navigation (Walk/Fly), if you're unsure what to assign this too, I would recommend using the middle mouse to trigger this action, as there are alot of keymaps already occupied for multiple other things.
At this point you might also wish to disable the action which pressing middle mouse does by default, so that they don't conflict, known as Rotate View (further up the list).
Making sure 'Walk' Navigation is set rather than 'Fly'
This *should* all be set by default, but in case a different Blender version has different defaults, make sure to set these:
Again finally, save your preferences by clicking the 3 horizontal bars at the bottom left of the preferences window and then pressing Save Preferences.
It should now be safe to close the preferences window.