Remove the tang bolt(s), the lock plate, and then all the pins or keys that hold the forestock to the barrel. YOu should be able to lift the barrel out of the stock from the muzzle. Sometimes( rarely) you are going to find a gun that has a bolt from the trigger assembly that mounts into the bottom of the tang, or breechplug.
That is the second reason for removing the lock plate. The first is in case the upper lock bolt goes through the tang, or breechplug. Removing the lockplate exposes the back of the barrel and bottom of the plug to view, so you can better see what else may be screwed to it that would otherwise prevent you from just lifting the barrel out.
On some foreign made guns, the screws that hold the stocks to the barrels are in or through the ramrod pipes, so you have to remove the ramrod, Also, before removing the screws. I always remove the ramrod before attempting to remove the barrel. Its the easiest thing to take out of the gunstock, before you begin to work on the barrel removal.
If you find the barrel is held with pins, you want to use a pin punch, or even a soft nail, slightly small in diameter than the pins, and push them out from Left to Right, as you look down from on the top of the barrel. Set the pins aside in the order in which they are removed, because often the length of the pin, and even its diameter is particular to a given hole in the stock. Make sure the pins go back in from right to left, and the same end of each pin also goes into the same place.
Oh, before turning out any bolt or screw, take a pin or scriber, or " scratch " awl, and mark the screw slot and some part of the stock or plate it holds to the stock with a short " witness " mark. This will allow you to return that bolt or screw to the exact same depth when you put the bolt or screw back in the gun when you reassemble the barrel and parts to the stock. Over-turning bolts is one of the principal reasons that locks begin to fail, or not work properly. That extra torque also puts stress on the stock wood, and on the barrel, affecting how the barrel vibrates. Removing a barrel is one way to change the POI you will get from that gun after you put the barrel back on.That is why some target shooters find ways to clean their guns that don't involve separating the barrel from the stock.
I recommend sealing the barrel mortise, the tang mortise, and the lock mortise with a good stock finish before the barrel is put back in the stock after that first diassembly. You will be protecting the wood of the stock from water and moisture, and from cleaning fluids, and oil that you put on the barrel and into the barrel to clean it or preserve it. Give the bottom of the barrel a coating of grease, or wax to protect it further from rusting while in the stock. Put enough grease on it that the grease oozes out the top of the barrel channel when you seat the barrel in it. Then wipe off the excess grease where the barrel meets the wood, and your gun is protected from rain. Find a grease that is tolerant of high temperatures and low temperatures. We now have some synthetic lubes that do wonders, even in very cold temperature. Water pump grease was what has been used for more than 100 years, but it may not be the best choice when the temperature exceeds 90 degrees.