Step 1. Turn off your Samsung phone with Power button at first.
Step 2. Press "Volume Up + Power + Home" button on your Samsung phone at the same time. When the screen turns bright, please release the three buttons simultaneously and wait for a while to enter Recovery Mode.
Step 3. When you are in Recovery Mode, you can choose different options by using "Volume Up/Down" buttons and then confirm your action with "Power" button.
For example, if you want to factory reset your Samsung phone, after entering Recovery Mode, you can:
Highlight "wipe data/factory reset" option using Volume Up/Down buttons and press Power button to confirm your action.
Then select "yes, delete all user data" option using Volume Up/Down buttons, and then press Power button to confirm.
Then choose "wipe cache partition" option and press Power button to verify.
Finally, choose "reboot system now" option and press Power button to restart your Samsung phone.
Now, you have finished the factory reset of your Samsung phone, and you can set up your Samsung phone as a new one.