Rocket Player version 2.0 introduces batch operations including add to a playlist, delete from device, and set an equalizer using its utility strip. Artists/Albums/Songs and items from every tab can be added to a new or existing playlist.
Add multiple items to a playlist
Select the multi-select button at the bottom right of the utility strip.
Press the check box next to the items to be added to a playlist.
Choose items from other tabs to be added sequentially (in order).
Create a new playlist, or add to an existing playlist.
Review the playlist - notice that the items are added sequentially from your selections.