Okay, to set up your stages, there's a number below the stuff on the lines marked with a #. That 0 should be changed to the number of levels (mushroom houses included) that you want in your world map. If you plan on using the same mushroom house text, you only have to put it there once instead of counting every house used in the world.
As for the mode, you type out the level setup and place it where the txt shows you to. For example, if you want a game in frag mode with a 5 kill limit, you'd type something like this.
The first 0 is to tell the game it's a map, not a mushroom house.
The second area is the map name, which in this case would be 0smw.
Third comes the mode number, which is where the mode chart comes in. This particular mode number is for Frag mode, but there are plenty of others to choose from.
Fourth is the goal, which is the number of lives or points that you start with or need to reach, depending on the mode.
Next is the points, which is how many points the winner of the match is awarded once the match is over.
Then comes the bonus list, this is a bit tricky to some people.
Let's say you want the winner to get a hammer. For that, you'd type 1p11 in that area. If you want to give multiple prizes, separate them with a , or a ; though at the moment I can't remember which. If one doesn't work, use the other, easy enough to fix.
About the W and the P, they are to separate world map items and powerup items, so just check the item chart to see what you need to type to get the item you want.
Next on that comes the name for that particular stop on the world map, it can be whatever you want.
Then comes the end world option, which tells the game if the world map ends at that particular stage or not. 0 for no, 1 for yes.
Here's where most people have trouble. The mode settings.
Reading through the code on page 1, you'll see the options for various modes followed by a dash and the settings you can use for that option. Here's an example.
#3 - Jail
#Style - 0 for Classic, 1 for Owned and 2 for Free For All
#Free Timer - None = 1, all other numbers greater than 1 are number of frames the jail will last (example: 620 is about 10 seconds)
#Tag Free - 0 = Off, 1 = On
#Percent Jail Key - number between 0 and 100 indicating the percent chance that a jail key will appear from a powerup block
Okay, these are options for Jail mode. Let's say you want the style to be classic with a 10 second free timer, tag free on, and no jail key powerup.
At the end of the level entry, you would put 0,620,1,0.
So let's put that on the end of a string for a Jail mode match and see how it would look.
It may seem a bit complicated, but that's how it's done. Oh, and for any mode that doesn't have any mode options, just put a 0 there instead.
One last note, you want to avoid putting #'s in the coding for your levels and such, since that tells the game not to read that particular line.
Hopefully this lengthy explanation helps.