First you need a few files to be downloaded onto your computer:
1. Bluestack (Download Page)
2. Bluestack MultiTool v1.21r1 (valid for Bluestack version 0.812 and below) (Download and extract)
3. BSNetBlocker version 1.0.3. (Download and extract)
4. UPDATE-Superuser-v3.2a.zip (Just download, don’t need to extract)
Rooting guide:
1. Install the Bluestack (Make sure you install the 0.812 version or below, go to Bluestack download page above).
2. Block the Bluestack Internet Connection by using the BSNetBlocker (Run as Administration).
3. Put the UPDATE-Superuser-v3.2a.zip in the same folder as BSMultiTool.exe.
4. Run the Bluestack Multitool (Run as Administration).
5. Choose option 1 and follow the instructions.
6. Wait for the rooting process finished, and your Bluestack should have been rooted.