You don't need to have a crafting job to create materia. You do however need to go to Ul'dah and talk to the guy near the Repair guy to flag the Materia quest (don't know the name of the person, maybe someone who can look them up real quick can find it), then you go to the north of Thanalan, and find the Goblin (moblin?) who will give you the item that will allow you to create materia (there are two other people there who will give you the DoL and DoH items to get Catalysts, and to perform the meld, but you need respective jobs above 18, and Cul, and Alc don't count).
Once you have that done, unequip the items that you want to convert (remember, you will permanently lose the items when you do this), then select them in your iventory, and you will have an option called Materia.
Select the Materia option, and watch the pretty animation, and it will tell you what you made.
To have it attached, you need a piece of gear that is meldable (see the (non)Convertable, and (non)Meldable text with your gear now? It is also easy to tell Meldable gear because they will have a weird dot to the right of them. And none of the dated gear is meldable, but they are all convertable). With that all said, a person of the right crafting level, with the correct catalyst, can meld the materia on an item. For now, I would recommend sticking with an LS member, though, I can't imagine peopel stealing low level gear and materia, but with the price and the time involved, I am paranoid about giving strangers my stuff...
Either way, you will need to find gatherers (or spend an obnoxious amount of gil on catalysts) and crafters (can't avoid this one) to meld your materia onto your gear once you make it.
You can also sell materia, which right now is probably the second biggest market in the game (second to catalysts).