Can I work with LinkedIn, Facebook business pages and personal accounts?

Yes, you can work with pages as well as personal accounts. Click on the '+Account' button that on the top-left corner of the screen to add an account. Make sure you're logged in to the right social account before you proceed.

However, as of August 2018, Facebook changed some rules for 3rd party software companies like DrumUp.  You are able to only immediate post to facebook personal accounts but cannot schedule posts ahead of time to those personal accounts unfortunately.  For more details, please go to this FAQ article.