Javascript Tags added to 3x advertisements on a wordpress website.

I have three advertisements running on my website. All three should have had tags added so impressions could be viewed by the client. Apparently, the freelancer I used previously did not implement this correctly. I have the code and the banners are in place. I just need someone with direct knowledge of this to upload the correct code and payment will be made once the client has confirmed they can see the impressions (this will be within 24 hours of completion).