By default, when a cell is highlighted and you press Enter in Calc, the cell selection jumps down. You can change the direction from jumping down to jumping right, left, or up.
Choose Tools > Options > Spreadsheet > Input.
Make sure the Press Enter to move selection option is selected, and change the direction in the drop-down list to the right.
Make sure the Press Enter to switch to edit mode option in the same window is deselected.