Log in to your Tumblr account and select from the drop-down list on your dashboard the blog to which you want to post your MP3. Click the “Audio” icon from the post types, and then select the “Upload” tab. Click “Choose File” to open a pop-up window displaying the contents of your hard drive, and then locate the MP3 file you wish to upload to your blog. Double-click the file to upload it. Edit the audio file’s track name, artist name and album as desired. If Tumblr pre-populated these fields with the track information, you can backspace over the existing text to type new information. Click “Select Album Art” to locate the image file for the album art on your hard drive. Double-click the image file to upload. If Tumblr pre-populated the album art and you’d like to change it, hover your cursor over the pre-populated image, and then click the “X” to delete it from your post. Type a description in the post-editing form, if desired, and format the text using the formatting tools in the form’s menu. Also add tags to the post, such as the musical genre, artist name and other information, to help other Tumblr users discover your content. Check the box signifying that you have permission to post the MP3 on Tumblr according to the site’s terms of service. Then, click the “Post” button to publish the audio file on your blog. You must have legal copyright or permission from the copyright owner to upload any media file to Tumblr. Per its terms of service, Tumblr may suspend accounts that have repeatedly violated the terms of service covering copyright infringement. If you’d like to post a song for which you don’t have permission from the copyright owner, you can instead use Tumblr’s embedded music service by selecting “Search” in the audio post form and typing the artist and song title in the search field. Select the available service from the third-party search results to embed the audio file into your post legally. Writer Bio