The smaller engines use black powder as a propellent and are fairly easy to ignite. Estes launch controllers will handle the igniters for all black powder motors which typically run from A to E impulse. The standard Estes Launcher has a 1/8" rod and is OK for up to a C engine. For the Estes D and E engines, it is usually recommended to use a 3/16" rod. I have an older Estes launch pad and both 1/8" and 3/16" rods fit. For the heavier rockets, I either stake the ends of the launcher legs to the ground with pieces of coathanger wire or lay something heavy on top of them so the launcher can't tip over if the rocket hangs on the rod. (It's happened to me.)
The Aerotech engines are a different propellent that is harder to light and you need a 12 volt launch controller. The Estes controller will not fire the igniters used. Also, the heavier rockets need a more stable base for the launcher and longer, larger diameter launch rods, typically 1/4" and 4 feet long. The Aerotech starter sets contain such a launch controller and pad, but the cost is on the order of $200. A G engine (single use) will run you $20 or so. The casings for reloadable G engines run around $60 but drop the per-flight cost to around $12.... assuming you get the rocket back. That may be a big assumption since a G can put a small rocket several thousand feet high and if you are not flying from a big, wide open field, you may never see it again.
I'd suggest you develop your building and flying skills on smaller, cheaper, rockets before stepping up to the larger rockets. If your flying field is small, focus on fat rockets to keep the altitude down and increase your chances of getting it back to fly again.
Regarding painting, you can color the rockets with Sharpies if you want. Acrylic craft paints work and don't smell much, but will tend to warp fins. My preferred finishing techniques is to spray a couple of coats of lacquer sanding sealer (woodworker's stores like Woodcraft have it) and then sand that smooth. I've had good luck with the Behlen brand. Let this dry a couple of days. Then come a few coats of lacquer-based automotive primer. The brand is not important, but look for words like "scratch filling", "high build", "sandable", etc. Sand that with 320 grit paper and let it dry for a couple of days. Just about any spray lacquer of enamel will work over that. If you don't have the patience for all the waiting, you can use Rustoleum primer and paint from a place like Home Depot. You can spray the primer and color the same day with some of their paint. Read the label to make sure that's the kind you are getting. If you are going to mask off and paint a trim color, let it dry well and then use a low tack (not so sticky) tape for the masking. The Tamiya tape in hobby shops is really good and the green painters tape works well also. The blue masking tape is a bit sticky and can pull up the base color. Stick it to your hands to take away some of the stickiness before using. Put on the decals and spray on clear. Apply the clear in light coats to avoid dissolving the decals.
