How do I get hands on Unreal Engine 4. Advice needed.

I have been using UE 4 since it come out free.
Previously I had no experience what so ever when it comes to 3d modelling.
Somehow I find it very hard to learn how to level building.
I did watch some of the tutorials online, whether is youtube or Digital Tutor.
And I followed some of the lessons and tried to build a simple level. 
And I did it. Bit by bit, step by step.
Then after a few months, I did not touch it again.

Now I wanna pick it up. 
I need some advice, if anyone here is familiar with 3d modelling/rendering. 
I have downloaded a lot of 3d models , and most of them are furnitures and stuff.
My goal is to import them into Unreal engine, and maybe play around with it a little bit. Like trying to build a house and put all the chairs and sofas in it. 
However the models I downloaded are not perfect, most of their uvmap are messed up. 
I do not know how to unwrap it… Coz if I remembered clearly, if you do not unwrap them properly, they are gonna look funny in the engine.

If someone has some experience , give me some advise (and probably some encouragement too ) how to continue.
I have a lot of free time, I do not wanna waste it. I am not hoping to become a pro level builder, but I wanna practice until I can play around with all the 3d models I have and without any sort of headache.

Thanks in advance.

For light maps, you can let Unreal generate the UVs. It doesn’t do a perfect job, but it’s pretty okay.

If the actual texture UVs are bad (the texture on the objects doesn’t look right) then you have to import the objects into Blender or 3ds Max or whatever and re-map the textures.

Oh. Thanks.
I think that I need to learn how to remap the textures.
Gonna try that.