There are a few guides out there that I would recommend.
For some general knowledge about how to set up your overview, check out the Overview Scanner
page on the evelopedia.
For a more in-depth tutorial you could also check out Overview Tutorial
You generally don't download overview settings because it's all about your personal preferences. If your corporation wants you to set up your overview in a certain way, I would recommend you talk to them about it.
Your overview settings are stored in the C:\Users\UserName\AppData\Local\CCP\EVE\c_program_files_ccp_eve_tranquility\settings folder.