API key application - unsure what some fields mean

[lekxens]

I'm trying to get an auth key but I'm confused by the application. My project doesn't exactly have a website and there's other basic stuff that I don't know what it's for, like a callback URL, sorry!
Could someone maybe very simply explain what the compulsory fields are for, please? I'm trying to use the Tumblr API for a uni degree project, to search for certain tagged posts so I can do a sentiment analysis, etc.

[cyle]

Hello there! Most of these URLs are a part of the OAuth1 and OAuth2 specification, such as the callback URL. You can read about what they do in the different "Authorization" sections of the docs. It's possible your application doesn't need to use them, if you won't be giving people a flow to "log in" and authorize your API consumer. In which case, it doesn't really matter what you put in those fields.

[sanmai]

The URLs you use you must control fully. I.e. http://localhost/

[lekxens]

Hello there! Most of these URLs are a part of the OAuth1 and OAuth2 specification, such as the callback URL. You can read about what they do in the different "Authorization" sections of the docs. It's possible your application doesn't need to use them, if you won't be giving people a flow to "log in" and authorize your API consumer. In which case, it doesn't really matter what you put in those fields.

thank you!! nobody needs to log in except for me. so in that case, what do i put into those fields, please, seeing as they're required to get a code? what format does it need to be, etc - when i enter something, i am getting back "this callback url is not valid"
as for the application website, what do i put? at the moment, i've put the link to my university's description of the course, i'm not sure if that's relelvent.