The easiest way to make a level is to copy a working level then work from there. Start by emptying the spawns then add your own spawns
my problem is that the character walks over the whole frame...i need a field of walking or walls or something but i dont know how to make this...
Yes, you need graphic editor such as photoshop to find playable field's size and define it with
z {min} {max} in levels.txt. It's easy to set as you only need to open the bg image, examine the image, define the field and find y coord of field limits then apply the coords as
z {min} {max}