There are two ways that your clients can login to their portal. The first is by going to the FCS Control Website. Once here, your client can enter in their email and password. By default, the log into option is set to 'FCS Admin.' Your client will need to change this to 'FCS View' and click on the 'Log In' button in order to successfully login to their portal.
The second and most commonly used option is embedding a login panel [to FCS] on your website. There is a HTML login panel attached to this help article. Once downloaded, you or your web developer will be able to open the attachment using a text editor. Once open, copy and paste the HTML into the location of your website that you would like your customers to login to. Feel free to customize the HTML as you see fit.