How are the missions made?

[Spectaculas]

I've been looking for some tool that opens those missions files, but I find out nothing. Any helpers? Direct link would be nice.  

[Baddo]

You can open mission PBO's for example with:

PBO decryptor

Then just copy the extracted directory to OFP\Users\YourUserName\Missions and you can then open that mission from the mission editor and examine all the additional files in the directory.