Hi! This is going to be fun for you!
First, congratulations on breastfeeding.
Skip the little jars. They're so expensive, and the nutrients are so broken down and in a lot of cases, even completely destroyed in the processing of it. Also, they often add bad things like food coloring to it.
Try just mashing up some baked squash or sweet potato (no oil, no seasonings), yourself. Freeze it and, when you're ready, pull out just a teaspoon or two. Thaw it by adding just a little boiling water (say, teaspoon or two), and strain it (I use a big tea strainer; use whatever). You want to make it wet enough to pour off the spoon - it really should be only a little thicker than breastmilk. Make sure to use only boiled water because it is sterile, and utensils that have gone through the dishwasher or that you have boiled (so you don't want to use plastic; only use metal because you don't want your baby chewing on boiled plastic - the chemicals leach).
For more information, get Super Baby Food by Ruth Yaron. She is WAY into it (and does a lot more than I have time for!), but you can take away from it what you like.
I do recommend starting with squash or sweet potato because they're very easy to digest. Also, starting with vegetables will help your baby to have an interest in flavors other than just straight-up sweet.
Also, never "double dip" and then return half-eaten foods to the fridge or freezer. No saliva can come into contact with the food if it is to be stored and eaten later. Bacteria are introduced and thrive in that, even in the fridge, and though they stop being active in the freezer, they "wake" right back up when they warm up again.
Those are the basics. Oh, and only introduce one new food per four days (some pediatricians suggest a week, to be safe). This way, if your baby has an allergic reaction, you know exactly which food caused it and don't have to subject your baby to a possible allergen a second time).
Oh! Couple more things: no matter what happens, always stay calm and happy while feeding solids to help prevent discipline and eating issues later in childhood. Resign yourself to plenty of mess-making. It's part of learning. You can teach him table manners in due time ;) Also, introduce new foods in the morning (but not when your baby is very hungry or tired; this is begging for trouble!), so that if there are any allergic reactions, they don't keep you up all night :)
Also, offer a little cooled, boiled water after every feeding. This helps prevent constipation. Just a few sips is fine.
Only do one feeding a day for the first couple of weeks.
Don't give him baby food instead of breastmilk. Baby food is ONLY on top of your normal feeding routine until he is at least one year of age! This is very important. In the meantime, introducing solids is really just a way of getting him familiar with the eating process, and getting his body used to solids. And this is very reassuring, you will see, when you realize how little actually gets down his gullet :) :) :)
Again, forget about jarred baby food. The stuff is no good. And making your own is actually very easy. Like cereal? Just make brown rice (I prefer quinoa because it's only 15 minutes) for you and your husband with no seasonings. When it's cooked, set aside some for your baby, let it cool and put it in the blender. When it's good and uniform, put it into separate containers (there are BPA-free plastic ice-cube-style trays, but intended for baby food, online) and freeze; you pop one out per feeding, it takes no time to thaw. You can add cooked, mashed lentils or split peas or whatever for more nutrition, and/or some veggies like broccoli, whatever, as your baby gets introduced to these one by one. Again, all very easy. Cook in batches, freeze, voila.
Really. Get the book. It's very, very helpful. Just use whatever you find most useful; skip the fancy stuff like how to carve a watermelon to look like a whale next summer if you wish!
Have fun! Take pictures! Or video!
L.