Empty the tank, catching the fish and putting them in fish bags for preference, or lidded buckets, or buckets with a cover as you go.
Remove all the decor and substrate and the filter heater. Make sure the filter stays damp as you'll start to lose the valuable bacteria if it dries out.
Then move the tank; you should always move tanks empty, as otherwise the seams may split, as they're not made for the extra stresses of being moved woth anything in.
When you get back, make sure the tank is straight on it's stand and has polystyrene under it if it's not a floating base. Wash the substrate before you put that back in as it's normally filthy (nothing against the previous keeper; that's just how it is!) and put in the heater and filter, but don't plug them in yet!
Half fill the tank and add your plants and decorations, then 3/4 fill. Check the temperature and make sure you've dechlorinated the water, then flaot the fish in the bags and acclimatise them as you would if you'd bought them from the shop; take extra mover this if the tank is from more than a few miles aways, as the water may be different.
Top up and switch on the electrics. Don't feed for two or three days so the fish have a chance to settle in.