As Draco18s is pointing out, you need to fully understand how Minecraft handles blocks. What you just said is closer to what you need to do, but we want to make sure you understand why.
Basically, from a "normal" object-oriented sense you would have a Block class and you would create an instance of it every time you had a block placed in the world. Logically this is good, but it has a bad consequence for performance -- the number of instances gets very large very fast. In just one chunk there is 65k possible positions to place a block so a world of just 20 chunks is going to have 1.2 million possible blocks. So if there was a instance for every block placed in the world there would be a serious problem with memory. So instead, Minecraft decided to have a single instance of each block class and instead create a "map" of where they are placed. That works great if the blocks are simple and unchanging as it is a very compressed format.
However, of course they then added the idea that some blocks might want to be varied. To do this they allowed a little bit more (just 4 bits) of data for each block position to allow variation -- this was called metadata. Some blocks used this for things like color (dyed wool), and some used it for direction, etc. But the key point is that the information that represented these things was stored in the "map" NOT in the block instance or class. There was no field in the wool class for the color, rather when the wool was rendered it looked up the data stored in the world data and applied the color then.
Now, the block class code sometimes needs to behave differently based on the metadata. Originally that was literally a matter of decoding the 4-bit values (that is why various Minecraft wikis and such you'll still see tables showing the values). But eventually this got more advanced implementation using properties and block states. Basically every combination of values of the properties creates possible blockstate. But ultimately these are still stored in a limited 4-bit mapping.
So putting it all together it means that you shouldn't confuse scope (like public or private or static or whatever) with this issue. Rather you must contain all your per-position information within a property, not within fields of the class itself.
Okay, assuming you understand all this... just look at other blocks which already do similar things, like a furnace or torch or something, and adapt their code to your specific need.