yewtreedigital

Hi, Im new to whmcs and im looking to add telecoms to my services my site is yewtreedigital.com and i currently have a designer working on a template for the checkout but what i would like to know is how i would go about adding this as a product so the checkout could be created like xlntelecom.co.uk/cheap-call-deals-sign-up1.aspx. Basically i need to offer customers the choice of having line rental with me or not and also having calls with me or not. i will be supplying different line types i.e. business and residential and also a number of calling packages. Any ideas for the product setup in whmcs?