So here we go.
As example for this lesson I'll just use the old version of the Blizzard map "Shakuras Plateau". First thing we do is obviously loading up the particular map in the editor and go to Map > Team Placement(Basic). Only requirements to do this is that you've already set the spawning positions. It should now look like this:
Right now spawn position 1 is selected. So what we have to do is simply select the starting position where the ally will be able to spawn. On this map this would be the one on top of sl 1 (sl 2). It will look like this now:
As you can see, the cross with the circle is the selected sl, the cross without is the ally sl (if you haven't figured it out yet, sl = spawn location). The black sl's are the enemys. If you have a rotational symmetry map or you just want to piss off the players you can select multiple ally sl's as in this picture:
This means that your ally may spawn at any location on the map. In this case we really don't want that to happen though. The goal is that allys spawn vertically of each other. So as already mentioned you select sl1 and on the right side sl2 which links those two sl's together. You won't need to set sl2 because you already did that in the last step. So next thing to do is to set sl3 which you select and check the box on the right of sl4. That should make it look like this:
As before, you won't need to set sl4 because you already did it in the last step. Congrats! You already set the spawning positions for 2v2. Of course you can do the same thing with more than 4 player maps. Just gonna require a bit more of box checking.
Now switch the tab to "Team Placement (Advanced)". This will determine the spawn positions in a 1v1 game. At the start both windowns (Teams / Linked Enemy Teams) should be blank. You now have to add teams (players basically). Click on "New..", check a box at sl1 and click ok.
You can give those teams a name, don't need to though since it won't matter at all. For this example I'll just call them Player 1-4. Repeat this step 3 times so you got yourself 4 Teams and link every team to an other sl.
What you do now is to select a Team (Player 1-4) and determine where the enemys will be able to spawn. This means that the boxes you'll check will be the possible sl's of that players enemy. You can see each Team's position by clicking on the Teamname.
In this example we only want to allow cross position spawning as in the TSL3 version of the map. So as seen in the picture for Player 1 we want to select Player 3 in the right window. For Player 2 we check the box at Player 4. Again those two settings will also set the two remaining sl's. Your Team Placement window should look like this now:
If you want to set the positions as they are in Blizzards original of Shakuras Plateau (both sl's on the right possible) you can additionally select Player 4 (for Player 1) and Player 3 (for Player 2):
You can also do the team settings in here. That means you'll have to create two new teams. I'm just calling them Team 1&2. Give Team 1 sl's 1 & 2 and Team 2 sl's 3 & 4.
I'm not even gonna post a picture of what to do now because there's only 1 box that you can check here.
And that my friends is how you set starting locations.
Feel free to post questions if you have any (but I really hope you don't because this is so detailed and idiot proof imo), tell me if I made a mistake somewhere (I'm really too lazy to go over the whole thing once more ^^) or just leave you're comments about how thankful you are and how I just changed your whole life. Donations will also be accepted. + Show Spoiler +
Cheers
FTR