I haven't played SS13 in a long time, what's new? Looks like there are a huge new amount of servers since the 2010-2011 days I played.
Even since 2011, there have been more changes than I could list. The majority of features have changed in some way since then, and a ton has been added as well. Goon, BS12 and /tg/ are still around, and the biggest 4 servers are those 3 and Paradise Station. /vg/ as well. I dunno what you played on, but BS12 isn't using Luna anymore, they merged with /tg/ a few years ago and started using a custom version of /tg/'s map. Because of that, the majority of servers are using some version of /tg/'s more recent map. Urist uses its own map designed by me and a bunch of people from the UMcS community. It's got its rough spots, but I'm constantly updating it and working on it. We're technically a branch of BS12, but we have a lot of features from /tg/ and some from /vg/ and NT, as well as some of our own features. By rough estimate, I'd say Urist is one of the 10 largest, english servers falling somewhere around 7th. And that's about what you need to know for background. I'd say google the BS12 wiki and the tg wiki to get a general idea of how things work now. The general idea and controls of it are mostly the same, but the interface has gotten a LOT better since 2010. Have fun!
Mapping question, but how do I set round-start spawning?
Look at Glloydstation for an example. You use the start area landmark, and rename it to the job. So, a start landmark named Station Engineer would be a spawn point for engies.