Documentation to create custom connector

Hi z88kat Could you check these documentation please 

• Power Query Connector Development
  https://learn.microsoft.com/en-us/power-query/handlingauthentication

• Creating a Custom Connector
  https://learn.microsoft.com/en-us/power-query/creating-first-connector

• Connector Certification and Deployment
  https://learn.microsoft.com/en-us/power-query/connector-certification

• Power BI Connector Extensibility
  https://learn.microsoft.com/en-us/power-bi/connect-data/desktop-connector-extensibility

And please check this forum thread also 
https://community.fabric.microsoft.com/t5/Power-Query/custom-connector/td-p/3195689
If this post helped please do give a kudos and accept this as a solution
Thanks In Advance