I need a delivery date/ delivery instructions facility adding to magento store

General information for the website: Online meat store
Description of requirements/features: I need a delivery date/ delivery instructions facility adding to magento store. We are getting too many customers not being in on delivery date so I want to add a system where the customer selects their own delivery date and can leave instructions, I would need to be able to set the available dates from within my magento control panel, I would also like it to be mandatory to leave a mobile number so the couriers can provide delivery updates.
I have extensions to add this functionality but not the technical know how to fully intergrate them.
Extra notes: I have uploaded a sample picture of what I would like, taken from another site, thats how I would like it to look but with another box added for the customer to leave delivery instructions, obviously I would need the chosen date and instructions to be shown on the order