public class AccountOwnerAssignment {

public static void AssignOwners(List<Account> triggerOld,List<Account> triggerNew){

    List <User> nonNamedAMs = [SELECT ID, LastName FROM User WHERE AM_Team_Account_Tier__c = 'Non-Named'AND isActive = TRUE ORDER BY lastName DESC];
    List <RoundRobinAssignment__mdt> accountReassignmentNumberRecord = [SELECT AccountReassignmentNumber__c  FROM RoundRobinAssignment__mdt WHERE Label = 'Master'];
    Integer currentOwnerPosition = accountReassignmentNumberRecord[0].AccountReassignmentNumber__c.intValue();

    FOR(integer i=0;i<triggerNew.size();i++){
        //Confirms that the Number of Clients have increased from 0 to a greater number
        IF(triggerNew[i].No_of_Clients__c > 0 && triggerOld[i].No_of_Clients__c == 0){
            currentOwnerPosition = calculatePosition(currentOwnerPosition, nonNamedAMS.Size());
            System.debug('currentOwnerPosition ' + currentOwnerPosition);
            System.debug('nonNamedAMs.size() ' + nonNamedAMs.size());
            System.debug('nonNamedAMs[currentOwnerPosition].ID ' + nonNamedAMs[currentOwnerPosition].ID + 'nonNamedAMs[currentOwnerPosition].LastName ' + nonNamedAMs[currentOwnerPosition].LastName);

            //Update Account with new Account Owner
        triggerNew[i].OwnerId= nonNamedAMs[currentOwnerPosition].ID;
          System.debug('triggerNew[i].OwnerId ' + triggerNew[i].OwnerId);
        }
    }
    // Update the AccountReassignmentNumber to the last AMs postion on the RoundRobinAssignment Custom Metadata Type record
    accountReassignmentNumberRecord[0].AccountReassignmentNumber__c = currentOwnerPosition;
    //Commit update to the AccountReassignmentNumber__c How do I do this?
}
    //IF the current positon is greater than the total AM count then the counter is reset else we increment to the next AM
    public static Integer calculatePosition(integer currentOwnerPosition, integer amCount){
        IF(amCount <= currentOwnerPosition){
            currentOwnerPosition = 0;
        } else {
            currentOwnerPosition = currentOwnerPosition+1;}
        System.debug('New currentOwnerPosition = ' + currentOwnerPosition);
        return currentOwnerPosition;
}}