I'm learning how margin works and wanted to understand how does liquidation price work in a margin position when using an exchange like Bitfinex? Their requirements is 30% equity.

Let's say I deposited $1000 in USD and purchased $2000 worth of Bitcoin at the price of $1000 each BTC.

I understand that my equity is $1000 which is what I deposited.

What is my liquidation price and how does one calculate it?

And what other factors do I need to know when if I wanted to hold onto this margin position for many months?