"You will not do as we are doing here today." This means that they would worship in the promised land differently than the way they were worshiping at that moment.
The eyes represent seeing, and seeing represents thoughts or judgment. AT: "everyone is doing what he considers to be right" or "now everyone is doing what he judges to be right" (See: [[rc://en/ta/man/translate/figs-metaphor]])
The land that God is giving to the people of Israel is spoken of as if it were a possession that a father leaves as an inheritance for his children. AT: "to the land that Yahweh your God is giving to you as a permanent possession" (See: [[rc://en/ta/man/translate/figs-metaphor]])