how to open a new layer or say new tab from new address typed using computer key board shortcuts. e.g. the way we use Alt+Enter for new version of IE.

You can set typed URLs to open in a new tab by standard, though not individually: Advanced Preferences > Browsing > General -> Open (choose "Typed URLs" from drop down list), then tick: In a new layer.

In K-Meleon you can used CTRL+T for open new layer and F6 key to write in URL bar.

K-Meleon in Spanish