Custom fields

Hi Can anyone point me in the right direction. I am developing an app and hoping that will be able to put it on the market place at one point.

What is the best method

Create several custom fields using the post method on zendesk ticket fields api then using the GET method to find the custom field ids for usage in my app. I'm currently hard coding custom field ids to store information related to that ticket pulled from a third party api.

Second option Post the information to a third party api database and call it each time the app launches? And primary field will be the ticket id. Also

how the hell do you use install requirements? Fields that will be used in the code eg API keys for a given third party app. Etc etc

Thank you and so sorry for all the questions. Aaron