OOOPPPPSSSS
Step 1 - turn off the computer...
Step 2 - Turn off the TV
Step 3 - Make Coffee
while coffee is brewing,
Aquire a quite room
a pen paper and other primative stuff
Step 4 - Have A cup of coffee and stair at the tools....
Step 5 - Brain Storm
Write down ANY THOUGHTS about the game...
ANY THING GOES !!!!
keep writing for as long as ideas come....
Step 6 - Go for a walk......
Step 7 - Have a cup of coffee and review notes
while asking "What did I mean by that?"
"Is that even possible?"
"That's good, How do I do that?"
Step 8 - next day?
Compile notes into feature that you know how to do
and move the fancy features to the "I'll need help with that"
pile. Be prepared to "Not use that feature in a demo".
Step 9 - Review notes again
Decide on 1 - Game Controls
2 - Game Options
3 - How to do the menus
Step 10 - Draw out all interfaces for all screens
Like Internet options
How many players (real/bots or single player)
Health bars and other status stuff
Radar views
How many monsters and locations of...
When all this is done,
Step 11 - Turn on computer
Aquire or make media for your game
Step 12 - By now you'll know what to do next....
A bit wordy there, But, as to your question on how to do level1 - 2 -3 and so on.... It sounds like you need a level editor. That may be where to start. Then in your game you simply "LoadLevel(1)" and so on. Then in that function, you delete all current objects and matrixes and load in the new from a file. Obviously a level editor will be needed before a game can be made, but even before that you'll need a level viewer. The editor and viewer apps will need to be created simulateously. As a new feature is added to the game, the viewer must be updated to show it. The common thread between the editor and the viewer is the level file. A format for your level file must be determined before anything else can be done. For my level editor I cheated... I'm using *.ini files as they are unstructured, but you could use .txt files to permit viewing with notepad.... Where to start.... good question indeed.