Set up a script with access to a Reddit account, collect the access token, the client ID, and the client secret. Once you have that, get a refresh token. Once you have that you can do:
let pants = Pants::new(
USER_AGENT,
"<access-token>",
"<refresh-token>",
"<client-id>",
"<client-secret>",
);
Then you can invoke things, e.g:
pants.me()
If your refresh token expires, you'll have to renew it:
pants.refresh_access_token()