How to generate application specific password

Hi all,

I am trying to use the REST API but I am stuck when it says that the user should generate an application specific password. I cannot find anything like this in the settings page, and when I use my regular password it doesn’t work.

Also when creating the client I do not know what the Authorization grant type options mean.

EDIT: I figured out my problem: I was creating the client on the beta api, looks like the password to use is the regular one.
However I still don’t know what the authorization grant types are.