Can't find .py files for new doctypes

Complete newbie here. Built a new site and a new app. Installed the new app. Want to add a custom script, but can't find the ".py" files for the doctypes I created.

The "Custom?" checkbox is left checked and greyed out. I am logged in as an administrator and I set the site developer_mode config to 1.

(I know I can add custom scripts from the gui, but still, it's sometimes more convenient to work on my own IDE).

Basicaly I want to create a table as a child ("Reciepe") of a doctype ("Dishes"). The table should have a data field (quantity) and a select field (raw_material). I want to populate the raw_material with var_name field from another doctype ("Raw Materials", which also has their prices, thus allowing me to calculate the cost of each dish).

Inside the sites directory, there will be site_config.json file. Ensure developer_mode is present in that file.

$ cat sites/dev.localhost/site_config.json 

Clear the cache b running

$ bench clear-cache

After that, go to Browser console and verify developer_mode, user.

If these 2 values are shown correctly in browser console, then Custom? will be unchecked and .py files will be generated.