can i cut my terrain in to separate chunks

hey i have make a big world. and the game ide is mmo,fps (**PC standalone**)
I just want to point out that I'm not super good at English so be nice to me ^^
and i'am so far noobY to uity

I have this terrain that I want to avail myself of.
info:
Width & Length 20kX20k : height 2010 : heigtmap resolution 4097 : detail resolution 1024 : detail resolution per patch 8. VIDEO

I also use the floating original script in my scene.
i think you see what i am trying to do, i basically need so my character camera is close on the origin in the space world all the time, that works whit the script floating original. and the terrain is huge so i need to split it in to "chunks" so i can load and unload this "terrain-chunks-parts" that is in my field of view.
somthing LIKE THIS Video or LIKE THIS and i knowe that i gonna use the LOD script or something similar like occlusion culling later

PS: i use UNITY FREE

so what i wonder is how do i split this terrain i have into square "chunks" ? for it is this terrain/map i whant to use.

do i need to do my terrain how i want it (for i still need to edit my terrain more for my roads and city/town gonna fit the way I want it) and then take the terrain in to a thread program (3D-modeling program) and make it in tiles and then add it in to unity again but like a object or how does it works?

I almost even thought to ask if someone can do it for me and get $50 . have been looking and looking but can not find any tutoriols to a easy way to do it , and it feels like it is way over my head, but i need it to be done. This is the hardest stop for me.

and another question belonging to this a bit, which programs is there that i can use which is similar to the occlusion culling that are free or atleast works for UnityFREE it does not need to be free as long as it is cheap

Thx in advance for your reply.

 

http://answers.unity3d.com/questions/763945/how-do-i-split-my-terrain-into-square-chunks-1.html