Step 1 - Copy player code from hypster
Step 2 - Go to your tumblr blog and click 'Customize' button
Step 3 - Click 'Edit Html'
Step 4 - Scroll Down and find 'body' tag
Step 5 - Now you may place player code after 'body' tag depending where you want to see your tumblr player
Step 6 - Click 'Update Preview' button and look for player on the right side.
Step 7 - Click 'Save' to save tumblr music player. And remember that songs can be restricted by content owners, so please verify if your player plays songs.