Custom Function Plugin

Hi,

I am developing a function plugin for appian.

I am following the steps in this page https://docs.appian.com/suite/help/20.2/Custom_Function_Plug-ins.html

am confused about one thing. Where do I actually include the java files for my plugin? I am inclined to put them under the functionPlugin package, but the documentation is confusing. 

This is my current path. I have appian SDK and google 3rd party library under referenced libraries. Is it fine to include 3rd party libraries, and did I locate them in the right folder?

The reason I am confused if I included the dependencies in the right folder is that in the url above. it is mentioned in step 14 to "Add any JAR files required by your custom function to the src/META-INF/lib/ folder." Technically my function depends on the ORTools library, but can't i just use it as a referenced library? 

this is what they recommend on the website. 

do the dots in  "com.example.plugins.<YOUR_PLUGIN>" mean nested folders? or they are literal dots? 

Also I noticed that in the twitter example, they have a package for process.runtime.activities. Is it mandatory? I don't think I need one. 

I am sorry if I am not very clear, and I would appreciate all the help you guys can give.

Thank you,