I presume your kids are of young age around say 5-8 years? i am assuming they could be the one's in the picture. If indeed they are of that age, it is easier to discipline them when they are at a younger age than when they are grown and think they know their rights. As the bible says allow me to quote this, " Teach a child in the ways of the Lord and they shall never depart from it". so i can say kids pick up a lot from their parents, so you as a parent needs to let that child know that you are the authority in that household, then the discipline can start. Remember do not be too harsh to your kids because then they will become scared of you which is wrong. The child needs to be comfortable around you,be able to trust and respect you and not be afraid of you. Those are the two most important things you need to keep in your mind as a parent. When a child is comfortable around you, they will not be afraid of approaching you about anything, whether you will grant them what they want or not, they will be able to understand your language, in that when you say yes or no, they will understand what you are telling them without picking any negative thoughts.Be your child's best friend and everything will flow. Be real to them, don't turn around and do the opposite. Kids like to be given reasons as to why something has not been done for them, or why they are not getting what they want, don't be too quick to judge them, but take time to listen, ask questions, hear them out, then explain as calmly as you can affirming them and loving them at the same time. When a child makes a mistake don't scream but ask a question and let them answer, then if the mistake warrants a punishment, explain why you are doing it and let them understand, and that child may never repeat it again if they are obedient that is.