All the Brands are very different but most of them uses same BIOS Key when every  go you want to go on BIOS make sure of all these things :

• Restart your computer /Laptop then Press the BIOS Key for Long time or press it again and again until BIOS  is Displayed.
• When you restart your computer /Laptop it shut down then its automatically starts this is called restart of computer /laptop don’t press the Key until it is off because Key will not work during this so make sure when computer /Laptop start starting then press Key.