Dungeon Core Simulator

At the crack of dawn, the world's mana coalesces with a frightening flash in the middle of the age old Hiberl Forest.
You rose, finding yourself as a dungeon core nestled into a modest grotto approximately 10 meters by 10 meters in size.
As a dungeon core, you have the ability to expand and populate your dungeon by spending mana. Dungeon cores gain mana by skimming off any excess mana radiating from any living beings present in their dungeon, so it's imperative you somehow entice visitors into your dungeon.
A screen popos infront of you and says:-
With the modest amount of mana you have to start off with, what will you do?

Day 1 (Dawn)
Weather: Rainy, Spring
Size: 100 sq. m., 1 floor
Mana: 100
Guests: 0