upload file to sharepoint from external web php / jquery

  api, javascript, php, rest, sharepoint

sorry if the theme is replicated, but I searched and I could not find what I need.
I am new to sharepoint and rest api topic.
I need to upload a file from my external website (php / javascript) to my sharepoint. The issue is that I search and find the rest of the sharepoint api but I don’t know where to start, if someone can help me how to start from scratch to connect to my sharepoint and upload a file. Thanks

Path where I want to upload my file:

Source: Ask Javascript Questions