I draw a very simple database design for my ASP.NET application and with a little help here and there I managed to implement my design...but I want to insert data to this ta
To try to answer your questions:
This is a pretty small design. My current project at work has 150 tables, arranged not unlike what you have.
Ideally to enter a new kid you'll have to only enter data in the Kid table. The easiest way to visualize this from a GUI point of view is to have one GUI table per database table. That way you can specify the Parents, Sponsors, Skills, Fields of Work, etc., on their own forms.
You'll have to ask yourself how much information is appropriate to supply for each kid based on the need. An interface that showed a list of kids with their parents, favorite toy, sponsors, skills, etc., will become way too crowded. Depending on your application, you'll probably want to be more specific on what data you show. For example, you might want to list all the information for kids when you specify them by name. If you need to query for kids who are sponsored by plumbers (sponsors' fields of work), for example, you probably don't care what their favorite toy is.