If you're looking to set up the Facebook Pixel, you'll need to copy and paste some code in to your website.
- Read Facebook's article on setting up the pixel
- In the "Add the Facebook pixel to your website" section, you'll see an option for "I update my website's code". Select this and read the instructions.
- Go to the Site Settings app in Aiir (you'll need access to this on your account), then go to the Head and Body HTML section.
- Paste the code that Facebook give you in to the Head HTML section. Be careful if there's already some code in there, you'll want to add it above or below any existing code. If you're not sure what you're doing, ask a more experienced colleague to help.
These instructions were correct at the time of writing.