Dont means de qui (for people), duquel / de laquelle / desquels / desquelles (for identified things) or de quoi (for unidentified things). Depending on the context, you may have the choice of what to use, or one may be mandatory. The two most important aspects of those rules is that:

• when asking a question, it is never dont (thus, de quoi te souviens-tu?, not Dont te souviens-tu?)

• after ce, it is always dont (thus, c’est ce dont je me souviens, not C’est de quoi je me souviens)

See this question for more details.