Dora Bas Rivka Silver O'H
Yes, There Are Two Paths You Can Go By...
Moshe tells the people that they have a choice: they can follow God's instruction manual and receive blessings or they can ignore it and receive curses. (People have free will and those are pretty much the only options!) When they enter the land, the people will stand on two mountains, Grizim and Eival, to enumerate the blessings and curses.
The people are not allowed to worship God in a novel or non-Jewish fashion. They must destroy the idols and altars of the Canaanites, but one may not destroy things used for the service of God. (This is why worn out prayer books and tefillin, et al., must be placed in "sheimos." See Talmud Makkos 22a.)
God will make known the site where His permanent Temple should be built (Mt. Moriah in Jerusalem - see II Samuel chapter 24). That's the place for sacrifices and tithes and all the other portions and offerings. In the desert, sacrifices could be eaten anywhere, but when the Temple is established, they would have to be eaten in Jerusalem. When they have entered the land and settled it, then God will reveal the chosen place for His permanent Temple.