Summarize:

Use a portable air monitor to test the air outside and make sure that the levels are normal before venturing there. You also need to make sure that any fires or flooding caused by the comet have subsided. Acid rain is also a potential result from massive fires putting pyrotoxins into the air, which would make going outside deadly. Have a reason to go outside, like being out of food or supplies, or hearing about other groups of people who survived and wanting to join them. Whatever the comet did not destroy can be salvaged for use, like food, batteries, water, or anything else you’d find useful from abandoned stores and houses.  Make sure that you are not stealing from anyone and that the goods have been abandoned by their previous owners to avoid confrontations. There is a chance that the location you try to scavenge in has already been sorted through, depending on the length of time you’ve been hiding out. If you’ve managed to survive the comet impact, there’s a good likelihood that others have as well. Hunger breeds violence and people will want to your steal supplies in order to survive.  Always try to resolve things peacefully, not violently. There may be other groups willing to share resources as long as you share yours. Always approach people cautiously, but not in a hostile manner. Non-perishable and canned food won’t sustain you forever, so you will have to get used to hunting and gathering your own food. Designate different people based on their strengths to search for food. Moving near the equator will be warmer and if the dirt is fertile, this will allow you to begin to grow food for consumption.  Having more people in your group will allow you to search for food more effectively. Moving near a large body of water will allow you to fish. Use survival guides to determine what foliage is good to eat and what is poisonous. A popular vote is a direct democracy and would work so that everyone had a voice in matters that affect the group. While having a final decision maker or leader is conventionally how smaller groups tend to act, having everyone’s voice be heard will hopefully ensure less fighting in your group.  As your group gets larger, the governance system becomes more critical. Make sure to hold everyone to the same standards.
Make sure the environment is safe before going out into the world. Scavenge for additional supplies and food. Prepare to defend yourself from desperate survivors. Move to a fertile place near the equator and plant vegetable seeds. Create a governance system for your new society.