I have been flying paragliders for more than 20 years, I am an instructor in France during the peak season, and in the winter I would go to Mexico, where I organize paragliding tours for visiting pilots/students.
The same way you must walk before you can run, you need to take it easy.
Actually tree-landing should not be considered as an option, though it may happen (and happened to me too!).
Basically, in most places in the world I've been teaching (Nepal, South Africa, Colombia, Mexico, France) it takes just a couple of days before your actual first "high flight". First you need to discover the equipment, and understand how to handle on a gentle slope : The "training hill". Just like riding a bicycle, it's not rocket science, but it's not so intuitive at first either. You need to get rid of earthly habits.
Aside from the practice, you also some theoretical courses, to understand the Do's and Dont's. Sometimes, depending on where you fly, or your paragliding school, you could go for a tandem flight, to debunk the fear of it.
Your first flight will be done in dead air : It will be a top-to-bottom flight.
You'll be checked/guided by one instructor on the take-off, then another instructor will guide you to the landing zone.
As you clock up more airtime, the instructor will let you fly almost on your own, only supervising your flight, and give you more slack. You will also do some in-flight exercises to discover how to handle a paragliding aircraft in more active (yet turbulent) conditions, before you really need it.
As you gain more experience, you may be able not only to stay up longer, but also go up : This is called thermalling. You could also do aerobatics, if that's your thing.
As a matter of fact, paragliding is not complicated but you have to take it easy.
It's actually a never-ending training, even though you will be in the air sooner than later.
In France, it is not a requirement to go to a paragliding school or get signed off by your instructor. You could actually buy your glider, no question asked. However most people would go to a paragliding school and would in turn recommend you do too : It prevent taking bad habits, help building up confidence, and drastically improve your life expectancy. ;-)
All paragliding accidents stem from poor judgement, lack of practice or technique.
It is human error that causes accidents.
Paragliding is not dangerous, but it can be risky if done carelessly.
People tend to confuse paragliding with skydiving. The illustration in Charlie's answer proves it.
Although paragliding comes from skydiving historically, they are completely different sports. Don't think that because you've some skydiving experience, it will translate well and quickly into paragliding. It may or may not. Beware.
I actually wrote an article about this topic (how to learn to fly). You may want to give it a look.