I'm not sure if this goes here or not.

So long as none of the files conflict, you can dump them all in one if you like. If you, say, have two mods that both replace CustomPlanets.xml, you'll need to resolve that before combining them.

how do I do this?

If you have two files with the same name, it would depend on where they were at. Files in Mods/XXXXXX/Data/ will replace any core files of the same name, so you can only have one for each. If you have multiples of any file like that, you'll need to open them up in a text editor and manually combine the bits you want, or just use one and toss the other (along with whatever changes it contains).

If the files are in the subdirectories below /Data/, then you should only need to rename them since those files are used in addition to the core files.

hey i just put the mods together ( dont ask how. i really dont now how to explane it)

assuming their the same thing for example particles & and radation tech tree and the original tech tree