What is the best way to invest, with a Bank or with an Investment Firm?

There is no "best way" to invest.  

But there is a risky way to high returns in a safe and low profit. At first, it is best to consult a finance manager and go low profit until he won a couple of years of experience. And if stocks go too high, just sell everything. It usually means they will go up or down, but the percentage down is much greater than is increasing. Unless the company in question comes with the new "hot" technology of the century ... like the iPhone.

Remember, 

You need prior knowledge, if you will invest in shares. You need to know what the company is planning, is working and what is happening financially to the company.