Parents immigration process _ Got Visa - not what are my next steps

[khide]

Hello,

My Parents got US visa last month based on Family immigration process they live in a foreign country and have never visited US. What are the next steps I have to take before they arrive to US and after they arrive to US.

When do I apply for I-485 form?
They only have a 6 month visa, afer the visa is expired do they have to go back or how does the system work? Do I have to submit an extention?

Can someone please help?

Thanks!