Make design adjustments in website software similar to shopify.com

I rented a webshop infrastructure from [login to view URL] which is similar to shopfiy.com. Now I would like to make adjustments to the design (bigger headline banner, different product presentation etc). I am looking for someone who can realize such adjustments in the program. Note that there is not an option to import your own codes, instead adjustments need to be made IN the program itself. Furthermore, a different code language is used called "rain". More information about this can be found here: [login to view URL] The RAIN language is used to make it more convenient to make adjustments, but some studying is required in order to understand the program. I need almost the entire website to be changed, so I am looking for someone I could contact every once in a while on the long term. Please let me know if you already have experience with .rain, or feel that you could do the job. Looking forward to your response!