Every choice you make sends you in a certain direction. Although we don't stay on one path, each choice adds up to make our current situation. We also make new choices based on experiences. So each new choice is based on the collection of choices before it.

One thing to think about here is the possibility that what the quote is saying is that only the things we choose to do are relevant to our actual lives.  Sure, there are things that happen to us that are not of our choosing in any way.  But those are not the things that really matter.  What really matters (one can argue) is not whether I have the luck of having good health or bad health, but what I choose to do in reaction to that luck.

So I don't think it is saying that nothing happens by fate or luck, but that what our lives are really made of is our reactions (which we can control) to those things that we cannot control.

Given Camus' association with existentialism, the quote aligns itself quite well with this branch of the philosophy.  Like Camus' work The Stranger, the quote alludes to the idea that individuals have only their free will to accompany them in their state of consciousness in the world.  The state of being in which human beings find themselves is one for the existentialist where there is only choice.  There is no transcendent totality, no absolutism, nothing upon which to guide human actions except for the issue of choice.  In this setting, there is only free will.  It is here where the quotation is applicable because "life," or humans' place in the world, is determined by the reality of choices.  An individual uses their own free will, and nothing else, to determine their state of being in the world.  The existentialist sees this as the reality that governs all human beings, all causality in the world.  Accordingly, for existentialists like Camus, choice and the ability to determine one's own identity through free will is what determines human consciousness, as "human behavior is based on nothing except free choice."