The questions are as below:
1. What do I need to start mining bitcoin?
2. Where do I mine bitcoin from?
3. Is it really efficient if your electrical bills are really expensive?
4. What is the most efficient way to mine for bitcoin?
I really hope that you guys can help me answer these questions.
I thank you all in advance.
1 - You need ASIC miner. It's pretty expensive thing.
2 - Out of thin air.
3 - No. e.g. if your el. price is around 0.2 USD/kWh you definitely won't profit. Try some mining calculator to check the profitability.
4 - Using the most efficient miner (which is Antminer S9 at the moment).
P.S. I do not recommend newbie to jump into mining. This is game for big investors. Miners are expensive and very loud (not for mining at home)... further profitability is disputable. Best way to get in this game is simply buy BTC and HODL.