When using small screen internet devices such as tablets, smart phones, and phablets (tablets having built-in phones), you will see ALL of the content shown on desktop and laptop computers. But you will see it in a different layout and with different icons for the login and menu controls.
Three screenshots show the key elements. When you first browse to IAAPsy.org, the home page (IAAP Central) will look about like this:
The "head" icon (arrow #1) will open the Login screen when tapped. The "4 bars" icon (#2) will open the Menu when tapped.
Tap the Login link to access the login screen, where you can enter your IAAP Username and Password, or request a Password Reset.
The main menu will look about like this. The ">" characters indicate that child pages can be reached when that menu item is tapped. The "X" in the upper right corner closes the menu.
In theory you can accomplish any big screen thing on a small screen - logging in, uploading documents and photos, etc. In practice you will find desktop and laptop computers easier to use for most tasks needing a login.