Go to prebid.org and click on download.
Find the AdHash adapter and select it.
Click on Get Prebid.js.
Follow the instructions in this prebid.org example.
Then change the src of the script to the path where you uploaded the file in step 4.
Replace the sample ad units with AdHash's ad units. You can check the integration on this page.
Replace the parameters publisherId and platformURL with the one provided by your Account Manager.