This does not mean "at this moment," but is used to draw attention to the important point that follows.
Ephraim and Manasseh will be mine
Ephraim and Manasseh each will receive a portion of land just like Joseph's brothers.
they will be listed under the names of their brothers in their inheritance
Possible meanings are 1)the rest of Joseph's children would inherit land as part of the tribes of Ephraim and Manasseh or 2) Joseph will be given separate land from Ephraim and Manasseh and Joseph's other children will inherit that land. AT: "as for their inheritance, you will list them under the names of their brothers"
This is another name for the town of Bethlehem. See how you translated the name of this city in Genesis 35:16.
(that is, Bethlehem)
The author is giving background information. (See: rc://en/ta/man/translate/writing-background)