ERP implementation

Newbie to ERPNEXT but experience with odoo, laravel php mysql bootstrap ERP, already installed ERPNEXT unattended installation on my ubuntu VPS. i need where i can start to implement ERP , for a bakery shop with purchasr order, workorder, employee, expenses modules for that. where and how to start from erpnext also if there any perfect tutorial step by step for customisation kindly guide me anyone from the forum. Advance thanks .

Follow this guide.
https://docs.erpnext.com

All you need to know is in there.

Thanks lot your help almost all documents are getting from this link , can i make custom app when i get all challenges are there that like as field calculation, fetch field , total amount in words , salary advance ,petty cash from custom script or server script .or customize from erpnext ?which one is best because is there any malfunction when update the version of erpnext.

Also more depth of script knowledge where i can get ?

for in-depth customizations, checkout the documentation below:

https://frappeframework.com/docs/user/en/basics