diff --git a/src/main/c/Georg/tictactoe.c b/src/main/c/Georg/tictactoe.c
index 1c602df..6888e7e 100644
--- a/src/main/c/Georg/tictactoe.c
+++ b/src/main/c/Georg/tictactoe.c
@@ -156,12 +156,16 @@ int* getMarkerParameters( char* input ){
     int firstArgument = input[index-1] - '0';
     int secondArgument = input[index+1] - '0';
 
-    array[0] = firstArgument;
-    array[1] = secondArgument;
+    array[0] = firstArgument-1;
+    array[1] = secondArgument-1;
 
     return array;
 }
 
+void setBoardMarker( bool board[BORAD_SIZE][BORAD_SIZE], int* params ){
+    board[params[0]][params[1]] = 1;
+}
+
 void handleGame(){
     char* input = getUserInput();
     int nextState = handleCommand( input );
@@ -182,7 +186,9 @@ void handleGame(){
 
     // gameCommand processing
     if( gameCommand == 1 ) { // set marker in field
-
+        int* params = getMarkerParameters( input );
+        setBoardMarker( GAME.board, params );
+        free(params);
     }
 }
 
diff --git a/src/main/c/Georg/tictactoe.h b/src/main/c/Georg/tictactoe.h
index 7cf6b60..7adc058 100644
--- a/src/main/c/Georg/tictactoe.h
+++ b/src/main/c/Georg/tictactoe.h
@@ -33,6 +33,7 @@ int handleCommand( char* input );
 void initializeBoard( bool board[3][3] );
 int handleGameInput( char* input );
 int* getMarkerParameters();
+void setBoardMarker( bool board[BORAD_SIZE][BORAD_SIZE], int* params );
 
 /* commands */
 commandFunction getCommandById(int id);
diff --git a/src/test/c/Georg/test_tictactoe.c b/src/test/c/Georg/test_tictactoe.c
index 5194ece..ffadb35 100644
--- a/src/test/c/Georg/test_tictactoe.c
+++ b/src/test/c/Georg/test_tictactoe.c
@@ -143,7 +143,7 @@ void test_handleGameInput(void){
 void test_getMarkerParameters(void){
     // arrange
     char* teststring = "set 3,3";
-    int expectedParams[2] = {3, 3};
+    int expectedParams[2] = {2, 2};
 
     // act
     int* actualParams = getMarkerParameters( teststring );
@@ -152,4 +152,21 @@ void test_getMarkerParameters(void){
     for( int i = 0; i < 2; i++ ){
         TEST_ASSERT_EQUAL_INT( expectedParams[i], actualParams[i] );
     }
+}
+
+void test_setBoardFields(){
+    // arrange
+    // arrange
+    bool board[3][3]={
+            {0,0,0},
+            {0,0,0},
+            {0,0,0}
+    };
+    int params[2] = {2,2};
+
+    // act
+    setBoardMarker( board, params );
+
+    // assert
+    TEST_ASSERT_EQUAL_INT( 1, board[2][2] );
 }
\ No newline at end of file