They said that the Sumerian Text is much older than the Bible itself, and that it copied most of its tales. Please clarify this claim made by an archeologist. Do you believe in the Dead Sea Scrolls? Are your interpretations coming from the Spirit or is it just pure research and human knowledge?
Good to make your acquaintance. I'll try my best answer your questions.
On Sumerian, well, I'm no Sumerologist, but it is true that the Sumerian texts are very old. Most people are unaware that even scholars in this field are not 100% sure of the translations of these cuneiform texts. Most translations of literary texts (the "stories" you ask about) are based upon later Akkadian translations of Sumerian rather than on a true understanding of Sumerian itself. That said, just because a literature has a "creation story" or a "flood story" (as Sumerian does – these are the primary ones your source is alluding to) does not mean ipso facto that they have anything to do with the Bible. Indeed, the only way there could be any relationship between any secular literature and the Bible would be if that literature copied or quoted or paraphrased or otherwise drew from the Bible. The Bible comes from God. It does not come from any secular literature, Sumerian included, despite the attempts of many unbelievers over the centuries to attack the faith of believers with this phony argument.
As to the Dead Sea Scrolls, no belief is necessary. They exist and can be seen in person in Israel or online (many images of them, at any rate). What they mean and what help they may provide for biblical criticism is another story. The non-biblical texts I have never found of any particular use. The biblical texts do demonstrate that our current text of the Hebrew Bible, aka "the Masoretic Text", is highly accurate. In other words, these scrolls support the principle that the Bible we have is the Bible God meant to give us (something we already did know by faith).
I am a Christian, and, like all genuine believers in Christ, I have the Holy Spirit (Rom.8:9). I have also done in my life what in my reading of scripture any Bible teacher should do: prepare diligently, research assiduously, pray fervently, and follow the Spirit uncompromisingly. But don't take my word for it. Were I deceiver, I would tell you "Yes, of course!" Christ told us to evaluate all teachers "from their fruits"; for "that is how you shall know them". Therefore, I always prefer to let these writings "speak for themselves". No human being is perfect, and no Bible teacher is inerrant. I do my best to find the truth and teach it with a clear conscience; I also make it my policy not only to give voluminous scriptural support for everything I teach, along with the arguments and explanations and reasons why I believe from the Bible what I believe, but also stand ready to answer questions and defend all the positions I have taken. I invite you to have a look at the actual writings themselves; doing so, I am confident that with the help of the Holy Spirit you will be well able to tell whether or not what you are reading is "good fruit" or whether it is otherwise.