This will hide the search button and block the "e" and "d" for users that are not admin.
This is not really giving you a secured Home Assistant, but it is good enough for use with kids.
Install:
Copy hide-search.js to /config/www/
The config directory is the place where your configuration.yaml for home assistant is.
If there is no www directory, just add it.
Add it as a frontend resource:
Settings->Dashboards
On the top right click the 3 dots and click Resources.
Click Add resource
Select Javascript module
put in url: /local/hide-search.js
Click create.
If it does not seem to work, clear your browser cache.