Questions to better understand instrumenting an Android app using the Appium method

I am having issues instrumenting the Android app to get tested via the "legacy method".  I'm looking into doing so using Appium

--Besides this page (link below), are there any others on SmartBear's site I should be aware of?

Set up Appium on Windows for Testing Android Devices | TestComplete Documentation (smartbear.com)

--Appium is freeware and open source right?

--All files and materials can be worked with locally right?

I hear "local cloud" and "local server" being mentioned in my research on this.  My setup and company policies do not permit me to have our app and other files hosted on servers that we do not own nor control.  This would be in contrast to BitBar which only allows cloud and severs controlled by them?