Both mean "to prepare oneself" or "to get ready".
sich vorbereiten (German):
"sich" is a reflexive pronoun, indicating that the action is done to oneself.
"vorbereiten" means to prepare.
připravit(vovat) se (Czech):
"připravit" means to prepare.
"se" is a reflexive pronoun similar to the German "sich".
"(vovat)" indicates that the verb can be used in different forms depending on the context (připravuji se, připravuješ se, etc.)"
