Confused about rakebacks and bonuses

If I were to join a poker room that offers 100% first deposit bonus up to $1,000, but when I make a deposit there isn't anything extra in there. How does this work? I'm sorry to ask such a noobish question, but I am so confused right now lol. I honestly have no idea how any of this works.

Edit: Sorry, I might have posted this in the wrong section. Feel free to move it.

when they say they give you a bonus it doesnt really refer that youll get double your deposit just means youll get bonuses the more you play. examples like tournament tickets, points for gaming, etc

The "100% bonus" is made to attract people, it may mean as mad_chils139 said you'll get bonuses in the future.

You have to earn it before it is released - each site has different earning requirements that you can find at their website.