1- go to your Profile Page (by clicking right on your NAME itself at top right of any page).
2- select the appropriate TAB in your profile page (Video or Audio, etc) (see my screenshot below)
3- then click the PLUS+ button at upper right to add a new audio item, and choose whether to upload a file from your computer, or to select one of your existing SoundCloud files. Enter the info required for your new Audio file or Video. Be sure you are complying with site rules on copyright etc.
Remember- you can go directly to your profile page from anywhere on this site by simply clicking right on your name at top right link.
Those irritated by grain of sand best avoid beach.
-Strumelia proverb c.1990