The feature of creating "Connected Teams" or "Child Teams" is not available in the Teams for Education version, it's only available for Teams for Business.
In Teams for Education, you can create a team and add other teams as members, but you won't have the option to create a parent-child relationship between teams.
You can create sub-teams or channels within a team to mimic the same structure, you could create channels within the parent team and assign different permissions to them, this way you can have different groups of people working together on different topics.
If you want to achieve a more advanced team hierarchy management, you can use the O365 Teams Admin Center where you can create teams, channels, and group them together, you can also assign permissions and roles to different teams, channels, and members.