Do I have to make new folder for those… or how does it works? I have win 7
@jappi67 Hi Jappi welcome to Pencil2D forums! To test the Nightly builds you jsut have to download the ZIP file from the respective link on the first post of this topic:
http://www.pencil2d.org/forums/topic/pencil2d-nightly-builds-2015/#post-27295
and once you have extracted the contents of the compressed file you can execute it like a portable app, no need to install! 
Bear in mind though that the nightly builds are unstable because the devs try to show progress with them. If you are going to test it with the intent to find and report bugs we thank you for that and we urge you to go to the Github bugtracker to see if your bug has already been reported:
https://github.com/pencil2d/pencil/issues
Thanks a lot and if you have any question let us know!