implement singleton design pattern and use it throughout classes

I have a console app where I solved one algorithm in it. I had all the logic in program.cs file, but then I was asked to implement Object Oriented design, and use separation of concerne more. So I started separating my logic in different classes, but in program.cs I had 4 global variables that I would use in my logic to solve the algorithm.

Now I have separated these 4 global variables and I've put them in a single class. What I need is to use these fields, in the same way as I had in my program.cs I need to use these 4 global variables throughout the classes and methods, where I assign different values to them.

I have tried to implement Singleton design pattern, as I thought this would suit my case, because I would instantiate the class only once, and I would store these values to use them in different moments, with their specific values.

So basically I would need one class to be instantiated only once, and to be used throughout other classes but also to preserve the values as I would with global variables.

This is my code

class cars.cs

                        public void ForbidenConfig(int number)
                        {
                            Collections c = new Collections();
                            Wheels3 w3 = Wheels3.GetInstance; // here I get the instance of the class

                            int k = 1;
                            Configurations[] block = new Configurations[number];
                            for (int i = number; i > 0; i--)
                            {
                                Console.Write("Test case " + k + ": ");
                                //bla bla bla another logic here
                                

                                //below I want to add data to collections
                                w3.Collections.Add(block[k - 1]);
                                k++;
                            }
                            c.AddCollections(object1, object2);
                        }

Now I have also this other class collections.cs where I have this code

    public void AddCollections(CarsConfigurations config, CarsConfigurations previousConfig)
    {
         Cars w3 = Cars.GetInstance; // here I get the instance of the class
        if (CheckConfiguration(config) == false)
        {
            config.SetPreviousState(previousConfig);

            //below I also add data to another field of the singleton class
            w3.AddCollections2.Add(config);
        }
    }

now this is my singletton class

    public void AddCollections(CarsConfigurations config, CarsConfigurations previousConfig)
    {
         Cars w3 = Cars.GetInstance; // here I get the instance of the class
        if (CheckConfiguration(config) == false)
        {
            config.SetPreviousState(previousConfig);
            w3.AddCollections.Add(config);
        }
    }


     public sealed class Cars
    {
        private static List<CarsConfigurations> ConfigCollections = new List<CarsConfigurations>();
        private static List<CarsConfigurations> ClosedStateCollections = new List<CarsConfigurations>();
       
        
        private static Cars instance = null;
        public static Cars GetInstance
        {
            get
            {
                if (instance == null)
                    instance = new Cars();
                return instance;
            }
        }

        private Cars()
        {
            List<CarsConfigurations> ConfigCollections = new List<CarsConfigurations>();
            List<CarsConfigurations> ClosedStateCollections = new List<CarsConfigurations>();
        }
        public static void ConfigCollection()
        {
            return this.ConfigCollections; // this line gives me an error ofcourse,  Member 'Cars.ConfigCollections' cannot be accessed with an instance reference; qualify it with a type name instead 

        } 
        
    }

Can I achieve what I'm looking for with Singleton design pattern..? If yes how can I manage it? Is there any other way? Can you guys please help me, I have this task to deliver, and I'm really out of time! Can you give any other ideas?

I would really really appreciate some help. Thank you in advance!