Welcome to a great hobby. +1 to what jdauria said.
Note that the sanitization really only applies to anything that touches the beer after the boil, so you don't need to sanitize your boil pot, etc. before boiling (but it should all be clean before starting).
If you are using tap water, you should remove the chlorine/chloramine beforehand to prevent off flavors. This can be done by adding a Campden tablet (one tablet will dechlorinate 20 gallons of water). The other way is to use bottled water, even distilled water is OK for extract brewing (but not for mashing grains if you do all-grain or partial mash). Some people will boil their top-off water to sanitize it and then cool it before the brew so they can add it to bring the total volume up to 5 gallons, some don't bother. Personally, I would boil it or at least use bottled or distilled water to be sure I didn't introduce any bad bacteria at top-off.
Definitely remove the pot from the heat while adding extract, then stir the extract in thorougly and return the pot to the heat. I like to keep a spray bottle of distilled water at hand for boilovers - spritzing the boiling wort will subdue the foam and prevent a boilover. Leave the lid off the pot while boiling, but you may want to put it back on while cooling if you are using an ice bath, just to avoid splashing unsanitized water into the cooling wort.
In Texas, your biggest problem in the summer is temperature control during fermentation, if you don't have a fridge or freezer to use for this purpose. Many of us use chest freezers with an external temperature controller to maintain about 65º F. Since you are just starting out and probably don't have one of these, there are some other ways - some people keep their carboy or bucket in a tub of ice water, and keep swapping out plastic bottles of ice from freezer to tub and back. If fermenting in a carboy, some put a wet t-shirt over the carboy, leaving the tail in the water in the tub so the t-shirt wicks up the water and stays wet. Blowing a fan over the t-shirt also helps to cool. Some build insulated boxes into which they put ice or plastic bottles of ice from the freezer. Also, keep the fermenting beer shielded from sunlight or florescent light (incandescent light is not as much a problem) - it should be in the dark for most of the time - this also applies to post fermentation - bottle in brown bottles, not clear or green.
If using a glass carboy, use a milk crate or BrewHauler to pick it up - read the threads on HBT about people who have been injured by broken glass carboys. If you are using a plastic bucket or Better Bottle, no worries.
BTW, John Palmer's book is available on-line for free (1st edition):
http://www.howtobrew.com/
I would also recommend buying the more up to date 3rd edition.
We bought a Bock Brew Kit. I am excited!! :-D However, being the first brew - a bit unsure, still. Wanting to make sure I correctly brew my first batch...
