@nickreadI will not recommend you to apply patch as you have no working experience with Magento. As you said you need to apply patches from 2014 which means you are using a very old version of Magento 1. Magento 1 will be gone next year.
I am not sure if you have budget or not. Only recommendation I have is hire a development agency and get the website build on latest version of Magento which is Magento2.
Problem solve? Give Kudos and select as Solution.
- Tarandeep
Problem solved?Please give 'Kudos' and accept 'Answer as Solution'.