Swipe from the top of the screen, then tap and hold on the Wi-Fi icon.
Tap and hold on the specific desired network, or tap on the Settings (gear) icon for that saved network.
Tap on the Modify (pencil) icon.
Tap on Advanced options.
Swipe down (even if it does not look like additional settings are in the window) to the IP settings drop-down menu.
Additional settings should appear in the window (such as for manually entering an IP address).
Once you have manually entered all network settings, tap Save.