Who leads the Jews now? Who is the High Priest? I have been told that there is nobody, how can they go on?
Because we (temporarily!) lack both a Temple & a functioning Aaronic priesthood, many of the Torah’s precepts are (temporarily!) suspended. Until the Temple is rebuilt (soon!) and the order of offerings (I do not like the mistranslation “sacrifice” for the Hebrew word korban, which actually is a cognate of a root meaning “to approach” or “to draw near/close to”) is reestablished, the other functions of the Aaronic priesthood (accepting tithes, administering the bitter waters to a suspected adultress, etc. etc.) are also temporarily suspended, as are most of us Levites’ functions.
Priests are direct male descendants of Aaron, via his two sons Elazar and Ithamar (Nadav and Avihu died before they could have children). See jewfaq.org/rabbi.htm#Kohein . Priest in Hebrew is cohein. Jews with the surnames Cohen, Cohn, Cahn, Kahn, Kahan, Kahane or Katz are probably cohanim (plural).
Levites are direct male descendants of Jacob’s son Levi (with priests being a group apart). See jewfaq.org/rabbi.htm#Levi . I’m a Levite (but our adopted sons are not).
Anyone who is of priestly stock (those Cohens, Katzes, etc.) or Levitical are priests-in-waiting/Levites-in-waiting. In Temple times, the priests & Levites were organized into rotations, arranged by family groups, so that everyone had equal time officiating in the Temples & an equal share of the various tithes. Up until the destruction of the 2nd Temple (and for a while afterwards), strict geneological lists were kept of priests & Levites. All those have long since been lost. Nowadays, many people with one of the priestly/Levitical surnames may not be actual priests (i.e. direct descendants of Aaron & his sons Elazar & Ithamar, in an unbroken male line) or Levites & many people without the priestly/Levitical surnames are probably priests/Levites. When the Messiah comes & active prophecy is reestablished, there will presumably be some way of figuring out who’s who for certain (it has to be certain; even “pretty close” is not good enough).
In the temporary absence of both a functioning priesthood & the Davidic monarchy, we are spiritually led by our Sages & great rabbis. They derive their authority from Deuteronomy 17:8-11.
5)With the temple gone, no new prophecy/writings, no kingdom, kings, or chronincles for the last centuries what do the Jews say about this. This seems significant to me, like that things have changed forever, yet they go on.
Please let me say the following:
We believe that God gave both a Written and an Oral Torah to Moses. The Talmud is a major codification of the Oral Torah. Through these (now written down) oral traditions, we understand how to understand the text of the Written Torah. (Ferinstance, the Oral Torah tells us that the adage “an eye for an eye, a tooth for a tooth, etc.,” was never meant to be taken literally but instead means that someone who gouges out another’s eye must compensate him monetarily for the loss of his eye. The Oral Torah tells us about the kosher method of slaughtering animals, referred to in passing in Deuteronomy 12:21. Etc. etc. See tinyurl.com/2ffy8 and tinyurl.com/2uyfp for a good intro on this very key Jewish concept.) Our Sages, i.e. those who are steeped in tradition and who have studied & delved into the text in great depth, are the bearers & keepers of these oral traditions & thus they are uniquely qualified to authoritatively interpret the Tanakh (what we call what you call the “Old Testament”) and offer continuing spiritual leadership & guidance to our people until such time (i.e. when the messiah comes) as prophecy, an active priesthood & the Davidic monarchy are all re-established.