The meaning of the numbers: 
 
Max Amount: The maximum number of spawned items that will exist simulaneously at this spawn point. 
Spawn Rate: The number of items to spawn per time. 
Max Distance: The maximum distance from the spawnpoint to spawn the items. 
Min Time: The minimum time in minutes to wait between spawns. 
Max Time: The maximum time in minutes to wait between spawns 
 
How to place an item spawn: 
Select an item from the list, fill in the desired numbers, click 'Place' to place the spawn gem, 
finally click 'Init' to initialize it. Ready. 