I would like to order one of these two open-source designs as Christmas gifts (doesn't matter if they're a bit late) :

http://www.thingiverse.com/thing:359145

http://www.thingiverse.com/thing:389075

Could you help me out ? How to fill the informations before uploading the files, if they are compatible ? I'm quite a beginner with these software and I only use linux distro... However I'm eager to learn.

Also, how will I/you make sure the tree is not too fragile ?

Thanks !