Graphics programming, and D3D, are hard. Sorry. There's a lot to learn and you're going to just have to work through it step by step. Hopefully you'll be able to get acquainted enough with it so that when the competition rolls around, the samples will be enough to refresh your memory. But I never much liked the samples as a place to start, not if you're totally new.

The easiest thing to do is probably to go here:

http://www.directxtutorial.com/LessonList.aspx?listid=9

And work your way up until you finish "Lesson 7: Simple Modeling". Once you've done all that, then come back and let's look at tackling OBJ files. X files might be a better choice if you have to write for the competition from scratch though, as OBJ is quite a bit of work to read and X is built in.

D3D Obj loading

As previously stated, graphics programming is hard and there's no way around that. However there are some excellent resources out there to help you learn.

Have a look at the RasterTek tutorials, I found them invaluable when learning all about Direct3D.

Its completely fine if you use something like https://github.com/bkaradzic/bgfx instead of learning all the low level bits of D3D/GL/Vulkan++ 12 Metallic Edition. Just do it if you enjoy it (or if there is good money on the table).

EDIT: Dont use bgfx, you'll be banned from the competition.