When something is "available", it means that someone has it, and that people are allowed to use it. For example, an employee at a gym might say:
Free yoga classes are available on Saturday mornings.
You can also say that "there is ___ available":
There's coffee and donuts available in the lobby.
And "___ has ___ available":
We'll have some more available on Wednesday.
I don't know if anyone's going to want to drink, but it's nice to have something available in case they do.