Looks like somebody gave you an NTRAK corner module that had additional parts added to make a small layout. By Break In/Run In time on an engine we mean to get new engine running smooth. This can take time. A new engine will run better and smoother after letting all the parts get broken in and settled in. Gears will mesh better, axles in bearing slots will rotate with less friction, the electric motor in the engine will have it's brushes seat to the armature. You do this by breaking in an engine. Run the engine in one direction for awhile, 15-20 minutes, change direction and run for another 15-20 minutes. I like to also change throttle settings up and down so the engine doesn't keep the same speed. This is a start. I will put an engine on a layout and let the engine run for a long time. Say put the engine on an NTRAK layout, and let it run for an hour. Changing direction and speed several time during the hour. Usually by breaking in an engine you will find that it starts running smoother, at a lower speed, with a lower currant draw, and if something is going to break, it will break early on.
I tend to run about half throttle for, like Tom said, about 10-15 minutes in each direction. I usually don't try and pull anything and I avoid MU-ing locos during this time. No sense in having one engine drag the other while trying to break in. Looks like a nice layout. You have free hand with the other three modules, it appears. Welcome to trainboard! Adam P.S. You'll get more response, in general, if you're more specific on your post title. Instead of "newbie question" I would suggest "question about breaking in locos" or something like that that's a little more descriptive of what you are seeking.
I run at slow speed in each direction for aboutr 2 hours. I have found that some engines need a little more wear for all the gears to find a "happy place" and settle down. Also, I use a liberal amount of grease rather than light machine oil.
That's a sweet little layout. If you ever wanted to expand it you could make a couple of plain-old-four-footers and stick them in there to make an oval.
