To add a device to a Linksys E3000 wireless router, first add the Media Access Control, or MAC, address of the device to the Wireless MAC Filter list of allowed addresses. Log in to your router and navigate to the Wireless MAC Filter page. Ensure that the filter is enabled and that "Permit PCs listed below to access the wireless network" is selected. Add the device MAC address by typing it into the first open box, and save the settings.
Once you have added the MAC address to the list of those allowed to access the router, connect the device to the router. Instructions for adding a device depend upon the device being added, but generally follow a few simple steps. As an example, to connect your Android-based device, ensure that Wifi is on and that your router's Service Set Identifier, or SSID, is displayed. Tap on the SSID and, if a password is required, enter it, being careful that capitalization is correct. To see your entry make sure "Show Password" is selected. Once you have entered the correct password, tap Connect to connect to router. Once connected, open a browser to Google.com or a different web-enabled app to ensure connectivity to the Internet.