OctoberCMS site from backup, layout and integration via API

There is a site written in OCTOBER CMS for the transfer from card to map raised from the backup. The site is one-page.
It is necessary to replace the images and change the texts on the TK.
It will also be necessary to make an integration with the payment service via API - sending data and receiving a callback. This will have to be done from scratch, we do not use the old payment integration.
It will also be necessary to correct the page with the result of the operation - so that the resulting callback is processed and displayed to the client.
Then the finished site is transferred to a new domain.
Respond if you work with october cms and have experience in api integrations. I will send the TK for evaluation. There are also projects related to php, october and integrations.