Hello Gytha,
indeed plenty of questions...
The way you are looking for is the "Tours Route", you can find some specific information in the sub-board on this site.
In general, the ways in France are waymarked:
- either as GR (little white and red marks)
- or as
Camino de Santiago (little yellow - often plastic - arrows, in Paris you might see some bronze scallops as well
The "booklet" is the 'créanciale' ( in French), you should get it either from a Jacobean organisation or from a typical starting point. (a church very often, or a specific "pilgrims office")
The best: buy a guide book in your language (or one you speak perfectly) - have a look and if you still have specific questions, ask them.
(f.i. where to start etc should be found in a guide book - I mean, they won't tell you where to start, but if you choose the town of XXX, in the guidebook you will find where the camino passes along to join it)
The Tours Route is the less frequented one, be prepared to be alone for many days!
If you prefer to find some company (especially of you age), start in Saint-Jean-Pied-de-Port, most people begin their camino there and continue on the
Camino Frances (situated in Spain!)
On this camino, you won't need a tent: plenty of abordable pilgrims hostals.
On the
Camino Frances, there will be plenty of people, but it might be reassuring to walk first with plenty of others than to be alone for weeks - especially if it is your first "big walk".
Your backbag should not be too heavy, so don't take too much stuff. But this alone might fill pages...
Oh, another important thing: good shoes!