You can change the permissions by right clicking and going to properties (or a similar option) in most desktop environments man, and you can double click a python file if you have python set as your default for py files.
and let me clarify that I don't use Linux on anything but a laptop that's too weak to run Windows.
I use linux on one of my old XP computers, I use a variant called ChaletOS on it since its lightweight, the one problem is the extremely complicated and annoying things you have to do to install a theme or even worse a single cursor.
And worse than that is compatibility with stuff like keyboards, if the keyboard uses a different set of drivers and their not available the generic drivers work but the bad thing is all the F keys (F1,F2, Ect) become shift and alt and ctrl becomes space.
There is a fix where I have to type something in the terminal to fix it every time it boots and its just too damn annoying, what's worse is that while wine works, anything with direct x you can forget about running and .net programs are worse to deal with, something always breaks, and its always compatibility, Mint was one of the better distros I have use but the xp machine could not run it very well.
And That's why I don't generally use linux on all my computers.
TLDR; Compatibility is hell, something always breaks, simple things like cursors are also hell to install.