Four questions about Hammer editing.

[deleted]

I've got a couple questions about Hammer that I can't answer. I also cannot find them online. I'll list them below:
Question 1: Prop_door_Rotating. I have an interior test, but I can't find out how to make the doors fit the wall! I see maps with doors that fit perfectly, but mine always have space on the other side of the wall.
Question 2: How do you make a 3D skybox? Pretty straightforward.
Question 3: Do any of you know anyone on Steam that can help me with map-making or a map-making team that accepts newbies? My best map so far was a city map which had one interior, with an unfitting Door (Q1) and a 2D skybox.
Question 4: How do you turn the VMF map files into BSP so they can be played? I changed the file extension like with Lua coding, but it didn't work.
Thanks for helping me all.

[GeneralTrivium]

Q1: Use developer textures to help visualize how big a gap you need to leave for a door. When positioning a door, turn off Snap To Grid to move it more precisely. Then adjust the brushes to close the gaps.

Q2: I haven't personally had to make one yet so I can't answer that.

Q3: Ehh, nope. However interlopers.net is a good community, and there are plenty of tutorials online.

Q4: Click "Run Map" at the top, it should be the image of a small globe.

[deleted]

Okay, I'm totally new to the mapping buisness using Hammer instead of Torque. I don't know what developer textures are, exactly. Not sure of the keybind for Snap To Grid. Adjusting brushes? I'm really THAT new. I'm doing minor entities and block detail so far. And I see everyone else doing 3D skyboxes on Garrysmod.org, so... I'll find out about that later.