Help fixing Google Adwords conversion tracking

I have multiple campaigns running on Adwords, however the conversions recorded are not adding up as real conversions in our sales funnel. I have followed all the necessary steps as provided by google to create conversions. I created a conversion under the category Purchase/Sale and named it sale, where each conversion has a different value. I was not sure whether to chose to track conversions on a page load or a click so I picked page load. I then gave the google tag code for the conversion to my developer and told him that he will need to customise the conversion tracking tag to include transaction-specific values. And to put the code on the thank you page. However, this seems to be an issue for him, he says there are no values on the thank you/success page? I also looked at google tag manger as an option so I wouldnt have to rely on the developer to change the tag code, but there is nothing working there either. Our website is built on nginx, using PHP. I can not give you access to the website root domain etc, only our developer has access for this. You could look at that page source of our website and if you supply me with whatever code needs to go on what pages on the website, that's no problem. I really need to make sure conversion tracking is properly set up for my campaigns, so I need someone to guide me start to finish and make suggestions. Where to put the tag code, and will the conversion tracking work on thank you pages without values. Or do it for me.