Edit the welcome page users are directed to when they log in for the first time
Navigate to Site tools > Dashboard > Site Administration > Template Directory > Template:Custom > Views > Live Placeholder > Community Member Welcome Page or Pro Member Welcome Page
Alternatively, go to the relative URL /Template:Custom/Views/Welcome/Community or /Template:Custom/Views/Welcome/ProMember
Open the page in Edit mode and add the information you want to display, which can include CSS, DekiScript, or JavaScript