Building a train depot with this asset is so difficult. I barely understood what icons and names of this assets pack means, and I have no idea how can I build a train depot now. Does it need road access? And what do the marks in the name of your assets mean? Is there any tutorial or explanation for them?

No, it's a decorative building as described in the descripotion and in the asset tags. It doesn't spawn trains nor it's functional, thus it doesnt have a train panel. Aside that, game does not have a functional train display.

I can't use...
Doesn't this mod display train panel ?

Slapping your old warehouse/depot doors on the side of these makes for a great bus repair depot as well.

nooo. now i can bulldoze all my railyardpart which i just build because of new buildings!!! ;)
lol, well I think I can use them at another locations.

Your killing it with these railyard buildings THANK YOU!