How Do I Move The Center Of My Model To The Blender Origin? My first post!

I'm completely new to Blender so you'll need to ELI5 I'm afraid lol

I've created a model in SketchUp then exported it as an obj file so that I could UV Map it using UV Layout Pro. I've then exported it in Maya as an fbx file and textured my model using Substance Painter. I've gone through this process using a student version of Maya which I can no longer use because I'm no longer a student so I've switched to Blender.

Now the problem I have is this:



I'm going to be using procedural generation to build my levels but as you can see from the pic above the pivot point is in a corner. I need my models to be rotating with the pivot point in the middle of the bottom face so that the corridor module can rotate 90 degrees clockwise or anti-clockwise without moving the corridor.

When I import the corridor into Blender I've worked out that I need to translate the model in the X and Y axes to bring the middle of the bottom face to the origin (0,0,0) but I don't know how to get this exactly in the right position. In SketchUp you need to have things 100 times the size so that you have the correct measurements in the Unreal Engine, so the cube that the model is made from is 300m x 300m which equals the model in Unreal being 3m by 3m. Is there a way of finding the middle of the bottom face:



And dragging that to the origin? Or am I thinking about this all wrong? Can I just move the pivot point to the center of the bottom face instead without needing to translate the model at all?

Sorry for all the n00b questions, I'm new to this modelling and game development lark and I need all the help I can get lol :D
I'm not sure there is an easy way.  The hard way that I can think of is to use the 3d cursor to move the origin of the object, move the cursor back to (0,0,0) and move the object to the cursor.  Unfortunately you then have to move the object origin back where it belongs.

The origin of an object starts out as the geometric center of the object.  It appears as a small yellow dot. Step by step to do this


select the object in object mode
switch to edit mode (TAB-KEY)
switch to face select mode (CTRL-TAB and select face mode from the pop up)
move the 3d cursor to the center of the face (SHIFT-S and select cursor to selection)
switch to object mode (TAB-KEY)
Move the origin of the object to the cursor (SHIFT-CTRL-ALT-C and select origin to 3d cursor)
Move the cursor to the origin (SHIFT-S and select Cursor to center)
Move the object to the cursor (SHIFT-S and select Selection to cursor)
Set the origin back to the geometry (SHIFT-CTRL-ALT-C and select origin to geometry)


There are other ways, but this one introduces you to using the cursor to precisely align objects.