Two separate things. Choosing and comparing equipment happens here; buying the equipment happens on the supplier's own website, from the listing on each product page. What this page arranges is the installation: an equipment list sent to installers for a quote, then a date with the one you pick.
Solink is a solar planning and product discovery platform. It does not sell panels or process payments, and there is no cart or checkout anywhere in it. Once you have chosen a panel, the product page links to the supplier listing on record so you can buy it there. Installation is arranged directly with a qualified installer, and any price you agree is between you and them.