How to make an array with custom indexes(MAPPING)?

Question

UPDATE:

struct TotalVotes {
    uint256 value;
}
mapping(uint256 => TotalVotes) public allVotes;

This works, BUT WHY DO I NEED TO use a struct? I only want single value which is an integer? Can't i do it without the struct?

Basically i need to store a dynamic amount of uint256 - which are IDs(unique identifiers).

How do I do this so I could then access numbers for each ID?

for example, i want to get uint256 values for ID, like this

myArray[123] and myArray[9843594]

TLDR: Need to store multiple uint256, that differ by ID which is an uint256. How do I create a mapping for it? An array where values are uint256, but you don't identify it by an address but by ID(uint256?)

I tried doing it like this

uint256 public numberOfVotes;
mapping(uint256 => numberOfVotes) public totalVotes;

but this doesn't work...