Very simple.
- Unzip the download into a folder and location on your PC.
- Start the Bot.
- Choose Axe-Fx II as the device on the SEND tab.
- The Input and Output ports should be selected for you.
- Click on the BROWSE button and browse to the folder location you chose to unzip to in step 1.
- Click on the BEGIN button and then choose the location you wish to overwrite.
It's all in the manual.