Custom Script for updating field value depending on value of another field

While creating new item or editing existing item I want Material Request type of an Item to be depending on its Item Group.

Please help me with custom script while adding or editing new item.

Thanks
Regards

Welcome to ERPNext,

This may help https://frappe.io/docs/user/en/tutorial/naming-and-linking

The above link you will find here https://frappe.io/docs/user/en/tutorial

Check out these https://erpnext.org/docs/user/manual/en/customize-erpnext/custom-scripts/custom-script-examples

Lots of instructional videos too https://www.youtube.com/watch?v=BgD7_ORlDwc