Here's three screenshots from the toolset. In the first, a few glowstones light your path. In the second it's welcome back to the light of the cave entrance. And the third.... the view from the cave entrance, off into the darkness you go.
You might want a torch or some other form of light. Official campaigns have to be nice about lighting up underground interiors for players so people don't complain about not being able to see. I don't. Naturally lit caves and dungeons for all! :-)