It literally means "Till the next meeting, guys".

"Ребёнок" is the most common word for 'a child' (of both sexes), but most common plural is, 'дети' (sg. дитя sounds somewhat poetic) "Ребята" is technically the plural of 'ребенок', but. 1. applied only to a group of _male_ children (girls are девочки and девчата) 2. to a group of male adults, usually when you address them directly, sometimes/often when you're (you being either male or female) a part of this group. Ребят, а давайте пойдем в кино? But not always, 'these guys' usage is also possible. "guys' is a good translation. 'до свидания' is the most common and neutral _polite_(!) way to say 'goodbye'. До - (here) till свидание, a noun, literally seeing-with. Usage is restricted to a few fixed contexts, one of them being 'до свидания'. Since 'ребята' (an address) assumes some level of familiarity, usage of a polite form in the same phrase (i.e, informal register was immediately changed into neutral/polite) means either: 1. Nothing. Just goodbye. I say 'до свидания' to my close friends/family pretty often. 2. He/she really means (s)he is going to see them again later.

до свидания=good bye! literally, it means -till the next meeting-