Magento 1.9.4.5 onepage chekout load time optimisation

Dear Freelancers, I have my store on Magento 1.9.4.5 with calrion onepage chekout installed in it. I am facing an loading time issue where my chekout page is loading in more than 20sec I want to optimise the performance of the page and make the load time between 2-3sec. If you have proper knowledge of Magento 1.9.4.5 then only BID on this project. I have a ready stage site for your working purpose.(Copy of Live site)