Programming relay on arduino

Hye guys
I want to contol a DC-motor with a 4 relay-module but with my program it doesnt work.
There are 2 pushbuttons, if I push on the left button the motor has to turn left and if i push once again the motor has to stop. If I push on the right button the motor has to turn right and again if I push once again the motor has to stop. Here you see my program.

const int drukknopplus = 22;
const int drukknopmin = 23;
const int drukknopN = 24;

const int relais1 = 34;
const int relais2 = 35;
const int relais3 = 36;
const int relais4 = 37;

int op = 0;
int opd = 0;
int neer = 0;
int neerd = 0;

void uitschuiven ()
{
digitalWrite (relais1, HIGH);
digitalWrite (relais2, LOW);
digitalWrite (relais3, HIGH);
digitalWrite (relais4, LOW);
}

void inschuiven ()
{
digitalWrite (relais1, LOW);
digitalWrite (relais2, HIGH);
digitalWrite (relais3, LOW);
digitalWrite (relais4, HIGH);
}

void motorstop ()
{
digitalWrite (relais1, LOW);
digitalWrite (relais2, LOW);
digitalWrite (relais3, LOW);
digitalWrite (relais4, LOW);
}

void setup() {
// put your setup code here, to run once:
pinMode (drukknopplus, INPUT);
pinMode (drukknopmin, INPUT);
pinMode (drukknopN, INPUT);

pinMode (relais1, OUTPUT);
pinMode (relais2, OUTPUT);
pinMode (relais3, OUTPUT);
pinMode (relais4, OUTPUT);

Serial.begin(9600);
}

void loop()
{
// put your main code here, to run repeatedly:
if (op == 0)
{
motorstop ();
}
else
{
uitschuiven ();
}

if (neer == 0)
{
motorstop ();
}
else
{
inschuiven();
}

if ((op == 0) and (drukknopplus == LOW))
{opd = 1;} else {}
if ((op == 1) and (drukknopplus == LOW))
{opd = 0;} else {}

if ((neer == 0) and (drukknopmin == LOW))
{neerd = 1;} else {}
if ((neer == 1) and (drukknopmin == LOW))
{neerd = 0;} else {}

if ((op == 0) and (drukknopplus == HIGH) and (opd == 1))
{op = 1;} else {}
if ((op == 1) and (drukknopplus == HIGH) and (opd == 0))
{op = 0;} else {}

if ((neer == 0) and (drukknopmin == HIGH) and (neerd == 1))
{neer = 1;} else {}
if ((neer == 1) and (drukknopmin == HIGH) and (neerd == 0))
{neer = 0;} else {}

}

Where in the code do you read the inputs from the buttons ?

How ARE your switches wired? You are not using the internal pullup resistors, heaven only know why not, so you MUST have external resistors. How are THEY wired?

The else {} crap is just stupid. Prove you are not a dunce. Get rid of ALL of them.

A further clue

The value of drukknopplus is 22 and you never change it. But you do
if ((op == 0) and (drukknopplus == HIGH) and (opd == 1))What are the chances of drukknopplus being equal to HIGH ?

You need to read the state of the pin rather than using the pin number itself in the tests.