The inner child is a huge resource in life, helping you fulfill your true desires and achieve goals. The more you connect with them, the easier it will be to achieve your goals, come up with something new, grow, and enjoy.
"The Parent" stores information received during parenting from parents, guardians, or other authoritative adults. These are social norms and rules of behavior, morals, and prohibitions. The main message of this condition is: "You must," "It's necessary," "You can't do that," "Don't be foolish."
"The Adult" is the calmest state of mind. It contains the ability to objectively view things and evaluate reality based on one's own experience and observations. The Adult is calm and self-controlled, makes decisions quickly, and behaves appropriately toward oneself and others.
The state of the "inner child" is imprinted in consciousness around the age of 4-5. It is responsible for originality, curiosity, and creativity, as well as for experiencing pleasant emotions. Impressions, joyful moments, and dreams mean a lot to the inner child, which tries to surpass the rules and invent something new.
The inner child exists in every person. However, it can be challenging to maintain a connection with them due to traumatic situations, such as the loss of a loved one, parents' divorce, a sense of control, and restriction. When a person grows up, their inner parent takes control and doesn't allow them to enjoy small things or do something irrational. People may not allow themselves to make mistakes. The parent dominates even over the adult, causing the person to lose their ability to gain an accurate understanding of the situation. They constantly violate people's boundaries and tell others what to do, as well as not knowing how to assert their own boundaries and easily fall under the influence of others.
Childhood traumas can affect a person throughout their life. When facing a difficult situation, even one resembling a painful event from childhood, they can fall into the same emotional state. Outwardly, it may seem as if they are upset for no reason, act aggressively, or suddenly withdraw.
To connect with your inner child, it is extremely important to work on childhood traumas: remember the situations from childhood that caused negative feelings, analyze them, and try to understand them.
The constellation technique can help: while sitting, imagine your parent sitting in front of you and tell them about your hurt feelings. Then put yourself in your parents' place and imagine yourself in their role, trying to listen to your own words from their perspective. At this moment, you may understand why your parent did this or that. Like a parent, give yourself feedback, talk about your feelings, and accept them. Constellation helps to better understand the feelings and motives of others and brings an inner sense of reconciliation, acceptance, and love. You can also imagine how your parent gives you a gift. You may even actually buy the gift you imagined as a symbol of parental love and care.
If you were hurt in your younger years and justice was not restored, you can start imagining how you would punish those who hurt you, as much as you desire. For example, you can imagine yourself stopping talking to them, leaving, stopping helping them, making them regret what they did. This childish revenge brings joy and lightness and helps to release accumulated emotions. 
It is also important to work on your perception of reality. When you notice that you are behaving strangely, but it triggers negative emotions in you, it is important to stop, track the sensations, name them, and understand where they come from. Are you projecting a situation from the distant past onto your friend? Constant observation and attention help develop the state of an adult while being at peace with the inner child.
Another technique is to create a magical safe space for your child. A secluded arbor, cozy room, green garden - it can be any space where your child feels calm and comfortable. Now, in every painful situation, the child can hide in this safe space where no one will hurt them. Children are often put in a position where their voice means nothing, and they must live by others' rules. Therefore, as an adult, it is important to set your personal boundaries. To do this, you must learn to say "no" to others.
The most important thing for the inner child is to let them do what they want and what they like. It can be a creative hobby, even if you're not good at it.