Download and install the necessary drivers. Download the newest Samsung drivers from here.
Download the
platform-tools zip
from Google.
Extract it somewhere - for example, %USERPROFILE%\adb-fastboot
On Windows 7/8:
From the desktop, right-click My Computer and select Properties
In the System Properties window, click on the Advanced tab
In the Advanced section, click the Environment Variables button
In the Environment Variables window, highlight the Path variable in the Systems Variable section and click the Edit button
Append ;%USERPROFILE%\adb-fastboot\platform-tools to the end of the existing Path definition (the semi-colon separates each path entry)
On Windows 10:
Open the Start menu, and type “advanced system settings”
Select “View advanced system settings”
Click on the Advanced tab
Open the “Environment Variables” window
Select the Path variable under “System Variables” and click the “Edit” button
Click the “New” button
Insert %USERPROFILE%\adb-fastboot\platform-tools in the text field