Available is a two-gender adjective with Latin origin dispose, which means something free, unimpeded, untangled, what can you dispose of.
Making it available is making something available, ready to be used. Ex: You don't need to worry, my house is always available to you. He was very upset because the item he wanted to buy was not available.
In some contexts, available can be synonymous with unoccupied. Ex: He must be unemployed, because he is always available to go out with his friends, at any time of day.
The word available can also relate to a person's willingness to do something. E.g.: While leaving the Court, the defendant was not available to make statements.
This word is often used to describe a person's openness to engage in a relationship or engage in some romantic and/or sexual activity. Ex: I ended my relationship 2 months ago and it's the first time in 5 years that I'm available.