When liberating a place after a apocalypse you need to make sure you're doing the world good ,not turning you and your group in zeds. So basically do not
Libarate a large country (Russia, Canada) Libarate a largely populated country (China,India) Libarate a dictatorship(with the dictator still alive) Libarate a land-locked country(zombies coming from all sides)
What you need Edit
A huge group(100-1000) A lot of time A good leader A few solders/police/hunters(only if it comes to the worst) A few medics/paramedics/nurses/doctors/surgeons/any one with first aid training Good melee weapons(axes/sledge hammers/swords/knife Reliable firearms(mini 14/AK if possible more recent ones AK-100 AK-74 AK-12) Long range bolt action rifles(lee-Enfield,Mosin Nagant,Mauser) A LOT of courage Good armor(not too much needed)
Of course the zombies are not just going to kill themselves for you so you need a plan. So this is what you should do: Give your men with fighting experience with your best guns and armor. Carbines and Kevlar vests if possible for more info go to armor and weapons. You have to decide how to invade. You could go by land, water or air. Give the rest of your men decent improvised armor and melee weapons. For more info see melee weapons. They will be your main attack. Your best solders will have to take important easy to defend and hard to attack places. When your normal men arrive they will join them and protect them from range. The easiest place to attack is a island because there aren't zombies to come in from a neighboring nation/city.
You need to build defenses to protect your zed free land. You should also send men around to search for any zombies who are not yet dead. You should also get rid of the bodies. To do this you could burn them or put them in a mass grave after having their heads cut off. You should also put them in body bags or if there not available rubbish bags with their heads away from there bodies.