I had to go, but here I took a pictures of where it's at. So you spawn here. Turn around, and you will see this. Go straight and turn either ways. Then just go straight and your at the lobby sign. I took a farther away shot.
Star I know this is really off topic but are you sure you want your brightness that low? You can turn it wayyyy up.
I see it was already answered, but I'll give you a bit more information. One way to get to spawn is to /spawn. You can't move for 30 seconds, and has a 1 minute cooldown... I think... You also can't perform this command in enemy territory (being in claimed land of an enemied Faction). Once you get to spawn, look at StarWar's picture, and right-click the lobby sign. A second way to get to spawn is to swim underneath the big spawn island itself. It's a floating island, and underneath is water. May take a bit, but swim to the center and you will see a sign that brings you A) to the top of spawn or B) straight to the lobby. I forget which one, think it's A, but not sure.p A third way to get to spawn is to die. Count how long you can hold your breath underwater, test to see if the lava is cold, or maybe see how many hugs you can give a cactus! Once you are a dead one, walk out of that little building and go right. You'll head straight to the lobby signs. A fourth way is going into the End at spawn, and use the End Portal thingy ma bobber (what is it called? overworld portal?) to get back to spawn One last way I can think of is by Nether Portal. Use the one at spawn, and walk back through it... should work... Hope these help!