My incentive was to create an app that reads files from my Yandex Disk (using the Yandex Disk API) using the bash from a Linux box. Unfortunately there is no much documentation in the Web (namely Google) about using the Disk API from the Web so I decided to write this short guide.
(1) Login with your Yandex credentials to https://oauth.yandex.com/ and create a new app. Give title, description and at the Scope section select the subscopes that you really need (or all of them) form Yandex Disk REST API.