The automatic updates update windows firmware, Word Preveiw to to full version and other window updates. If there set to update automatically they will update themselves and may occasionally need a system restart for some updates. These settings can be changed in control panel > system and security > windows updates. The Store updates can be accessed for within the store itself.
There are two ways to get to Windows Update:
1) RT version - Charms Bar > Settings > Change PC settings > Windows Update
2) Desktop version - Charms Bar > Search > Control Panel > Windows Update
(It's not a bad idea to pin Control Panel to your Start screen)