How to setup One Trust cookie baner to work with Google Tag Manager

At the begining we need to be clear what is:

• Google Consent Mode - Google Consent Mode is a mechanism built in Google Tag Manager which is responsible for adjusting Google tags behavior to user consent settings. It will for example block data transfer to Google Analytics if cookie consent for analytics_storage will be not granted but will allow data transfer to Bigquery without user specific information.
• OneTrust Autoblocking - this is a mechanism included in One Trust cookie solution that blocks/alllows cookies automatically by scaning your website regualry and categorize specific cookies to the corresponding categories. 

 Then we need to do the following steps:

1. Add your new website to OneTrust panel to allow OneTrust to scan it.
   To do that you need to click: "Add website" in OneTrust tool
   
   
   
   Then you need to insert your website details and click "Scan&Configure"
   
   
   
   Next step is to create new custom experience kit. Experience kit represents a geolocation rule group and each of the templates assigned to the rules within the rule group.
   
   
   
   After that you need to add your name of kit, and choose language your users speak:
   
   
   
   
   Choose which frameworks you need to be compliant with. In this case we use GDPR because website operates in Germany.
   
   
   
   Then you need to choose banner layout and customize it to suit your website.
   
   
   
   The same with preference center:
   
   
   
   On the last screen you will be asked just to review settings once again and confirm it.
2. Install One Trust scripts on your website.
   You need to go to the scripts section of OneTrust cookie consent tool and copy from there cookie banner script and paste it on your website.
   
   
   
   You should paste the code into your website. 
   In the script sections you have also two other scripts: cookie settings button and cookie list. Both of them should be implemented on the website. Cookie setting button should be implemented somewhere in the footer, cookie list on your privacy page.
3. Adjust your Geolocation rules
   • Turn on: Google Consent Mode for each geolocation rule connected to your website:
     
     
   • Turn on: Capture of user consent
     
     
   • Make sure each Geolocation Rule has the appropriate template assigned to it.
     
     
4. Customize your templates
   If you did not adjust your templates appearance during first step you need to do that now. Adjust colors, behavior and content.
5. Publish your scripts
   Go to scripts and then "Publish production"
   During publishing remember about:
   • Enabling Cache Buster
   • Enabling Automatic Blocking of Cookies(all technologies that you manage in your GTM should not be blocked by this so you have to uncheck some positions).
6. Adjust cookie sources
   Go to Cookiepedia > Categorization and chose your website from the list. Check each cookie, and if you find any cookies which are set by your tags in Google Tag Manager make sure that you delete all sources for them. To do that you can select specific cookie and go to the source settings. This action will prevent OneTrust blocking tags that you already implemented in Google Tag Manager.
7. Make sure you set up Google Consent Mode in your Google Tag Manager for all tags.
   How to do it you can read here: How to setup Google Consent Mode in Google Tag Manager
8. Test cookie consent settings impact on your tags and cookies.
   You can do that checking your browser cookie list to see what is blocked and what is active depending on user consent. Also in Google Tag Manager debug mode you will be able which tags are blocked or not.