Selbst vs sich
can someone tell me the difference between the two, in the dictionary they have the same translation
The meaning is very similar for both, but grammatically they are used in different situations.
"Sich" is a Reflexiv personal pronoun, it is used with some verbs when the Objekt (suffers the action) is also the Subjekt (performs the action). For example: "kleiden"="to dress" / "Die Mutter kleidet ihres Kind" = "The mother dresses her child" / "Sie kleidet sich" = "She dresses herself". Some verbs are always Reflexiv ("sich kümmern"), many others can be used as Reflexiv ("kleiden"). A similar situation is when "sich" behaves as Reziprokes Pronomen: "Deine Eltern lieben sich" = "Your parents love each other".
Another situation is when the English form "self" is used not to indicate that someone is doing something TO himself, but that he is doing it BY himself. Example: "Ich möchte meine Fahrrad selbst reparieren" = "I want to repare my bike by myself". You can see that in this case you use no Reflexiv form, you use "selbst" instead.