Pick up a finishing hydrometer to check the specific gravity. The graduated markings on a finishing hydrometer are spaced farther apart for easier and more accurate reading. These hydrometers read from about 0.980 to 1.020. If you brew kits for a while you don't need to check the original gravity. The OG will be as the recipe states when all the fermentables of a kit are used and the volume in the fermentor is correct.
An adhesive thermometer strip on the outside of a bucket or carboy is one of the best ways to monitor the temperature of the fermentation. You won't need to open the fermentor to measure the temperature. Place near the 5 gallon mark. This will keep it out of the water if you may use a swamp cooler/heater in the future for temperature control.
The remnants of the krausen ring can be left above the beer until you rack to the bottling bucket. The hop debris in the dried ring can sometimes be bitter.
I don't take the first SG reading until around day 10 to 14 after the active fermentation had started. I'm not going to bottle for at least three weeks anyway. It takes about that long for the beer to clear in the primary. I don't want excess suspended yeast and other sediments in the bottles. I like to pour the entire contents of the bottle if at all possible. The second SG reading is 5 days or a week later just to confirm the fermentation is complete.
When you have emptied the fermentor check the volume markings, if marked, by adding a measured 5 gallons of water. Sometimes factory markings are not correct. (Instead of dumping this water add some PBW for cleaning.)
Welcome to the world of home brewing.