If you read my previous zombie survival blog, you know the basics. If you're still retarded enough to think the mall is a great idea for a fortress, read through this article to learn why you're an idiot.
To recap, you have already arrived at your chosen fortress (the prison) and you're close to the alpha male in charge. You still have supplies for weeks or even months. But you need to think like a chess player. 3 moves ahead, at least. Once you settle in (2 or 3 days), you need to convince your alpha male to organise a supply run.
What do you need? You need groups of armed people and supply trucks. The prison should have some. Take 2, 3 max. Be sure there's 3 teams:
The Leaders - that's you and the alpha plus your bodyguards. You give out orders to the Ants. The bodyguards should be armed with pipes and shotguns. Their job is to look out for any zombies inside the perimeter and to intimidate the people you encounter.
The Ants - the ones that's gonna pick up the stuff and take it to the trucks. They should only take orders from the alpha (you need to tell him the orders indirectly, so he thinks he's in charge). There should be more than one group. 2, 3 or even four with their own methods and free to work how they like, as long as they concentrate at taking what the alpha ordered them. Each group should be armed with pipes in case of an encounter and be in contact with the alpha, so the bodyguards step in in case of zombies/people trying to stop them.
The Enforcers - This group is very important. They secure the exit, the trucks and there should be at least 2 snipers on the roof. They should also be prepared to put on new fences (you should bring some with you. In case you break through a defense on arrival. Padlocks should be great for attaching them, since it's faster than welding them shut.
What's the plan? You drive into a mall, which is most probably holding some survivors. If it's not, you could secure it, but the most possible outcome is that it's outrun by zombies outside and there's people inside. Be sure to clean up the area from zombies, but only from the side you enter. Break through the fence and set up a new one. Enter and say you're from the police and you're here to evacuate the survivors. For their safety, all should step up to the main hall and drop their weapons, if they have any - for safety purposes.
This is the part you realise how retarded you were if you chose to stay at a mall. The mall inhabitants don't have weapons. You do. Lock them up, if possible. You get to take whatever you want and leave. Be sure to leave the people alone, unless you need to show you're serious, then shoot one in the leg or some shit. Get to the supplies, and remember the correct order of what you take:
First you take water. Gather as much as possible. It's the most essential supply.
Second, take the smokes. Surprised? Money is worth shit right nyao. Cigarettes are the new currency. Be sure to take all available there.
Thirdly, there's alcohol. Gather the finer drinks, the most potent ones. Be sure to have a lot.
The last supply on the list is food. Take the smaller fridges with meat with you - they might come in handy. Take all that's canned. Forget shit like snacks or chips. It takes up place. Take sweets, though. Even if you have to leave before you gather much food, remember you have a supply at the prison. The first supply run is water, cigs and alcohol. Oh yeah, take some bathroom supplies too.
When you arrive at your stronghold, be sure to launch a party with a lot of alcohol. Thank your team for the great mission and the survivors at your place for trusting your leadership. You don't get drunk, though. Be sure you and your alpha stay sharp. You need to assign trusted people to guard the supplies. Assign someone to give out rations. Keep all the cigs and alcohol. Those will be given out as prizes. Of course, your bodyguards and the ones securing the supply will get a lot of cigs and alcohol, plus more rations.
From there you can manipulate people into doing stuff for you. You and the alpha have unlimited access to the supply. Use it wisely.