Thank you so much for posting your idea, there is a lot of information available about the Intel Galileo boards. I'm going to share some of the most useful links that we have.
The main page about this board you can find it here: https://software.intel.com/en-us/iot/hardware/galileo/dev-kit, it has a lot of links where you can find information about documentation, code samples, downloads, etc.
To help the beginners we have the getting started guide, please check this link: https://software.intel.com/en-us/get-started-galileo-windows, this guide is very useful for the Galileo users, and you can choose the OS of the host computer.
About all the software available we have the page: https://software.intel.com/en-us/iot/hardware/galileo/downloads, maybe this is the page that you are looking for, you can find here links about the BSP, the Latest Yocto Poky Image (and older versions).
Take a look at this link too: https://software.intel.com/en-us/iot/hardware/galileo, it has a lot of general information like the first one.
I hope you find this information useful.
Have a nice day.