Does such a phrase exists in English?
I think English is probably less formal than your language, so there is no set formula. Is it necessary in an English context to have all that introductory stuff? We might start of saying, hi, my name's this, I work at that, and today I'm going to talk about this. *Right,* content content ..... Right, represents a change of focus, "let's get down to it". Not sure if that's helpful. Listen to how others make such presentations. Hopefully you can find online people giving a talk in a context similar to yours.
"That being said, ..."
Depends on the context. In Britain I might think that it is a bit strange to say (every time, in every context) something of the nature of "having said that" after an introductory few sentences. Incidentally, it should be "Now that I have said that,....." Note the addition of "have". But note that I am British, the omission of "have" might be normal in the USA.