Aight.. this is probably the best way to make a simple bound.
Start off by doing all of the normal things (ie, map properties, etc). If you want music in your bound, and you dont know how to loop it (Its pretty simple) then just ask.
First, always do your terrain; a lot of people will just do random terrain for obstacles, then do random explosions. If you want to do a specific obstacle, place the terrain in the order you see fit.
After doing your terrain, do a trigger that will create one zerg zergling for each player at a location. Make sure that you do this trigger for ONLY one player; if you check the box for P1, P2, P3, etc, it will create three lings for one player instead of one.
[Players]
Player 8
[Conditions]
Always
[Actions]
Create 1 Zerg Zergling for Player 1 At [Location]
Create 1 Zerg Zergling for Player 2 At [Location]
Create 1 Zerg Zergling for Player 3 At [Location]
Create 1 Zerg Zergling for Player 4 At [Location]
Set Obstacle 1
Make sure you do it for how many players there are.
After the lings are created, a switch will set. This is called a boolean variable; basically, it is a "True" or "False" statement. In a simple trigger system like this, if it is "Set" / "True" something will occur (The actions).
[Players]
Player 8
[Conditions]
Obstacle 1 is set
[Actions]
Create 1 Terran Medic at Location 1:1
Kill All Any Unit For All Players at Location 1:1
Wait 200 Milliseconds
Create 1 Terran Medic at Location 1:2
Kill All Any Unit For All Players at Location 1:2
Wait 200 Milliseconds
Create 1 Terran Medic at Location 1:3
Kill All Any Unit For All Players at Location 1:3
Wait 200 Milliseconds
Preserve Trigger
Note: If the obstacle is too hard, you can slow it down by merely editing the wait time to be longer (ie, 400 milliseconds).
This will make the obstacle do a "loop." It will keep going until the switch "Obstacle 1," is not set. If a player reaches the end of the obstacle, you will obviously want to end it and start the next one:
[Players]
All Players
[Conditions]
Current Player brings at least 1 Zerg Zergling to Location 2
[Actions]
Clear Obstacle 1
Set Obstacle 2
This will set the next obstacle and cancel the first one. You repeat this process until they reach the final location or end. Then you end the scenario in victory for the current player (Or end it in defeat if you want to be a jackass).
Thats the most basic form of a bound. Hope I could be of help.