You already registered at OwlAI.cc right?
1) Right-click and "View page source"
2) Copy from the comment "start copy here"
3) Copy to the comment "end copy here"
4) Paste into your own website page
Install the free plugin 'WPCode'. Paste your OwlAI snippet there. Click Save. Done.
Go to Settings > Advanced > Custom Code. Paste the OwlAI snippet in the 'Head' section. Select 'All Pages'. Click Apply.
Go to Website > Website Tools > Code Injection. Paste the snippet in the 'Header' box. Click Save.