To help you align objects on a page go to Arrange > Show Grid or Arrange > Snap to Grid. Set the spacing of the grid in Preferences > General.
For a measurement guide show a ruler along the top of the Page view area by choosing Format > Text > Show Ruler (Command+Control+R). With a specific text box selected for editing, the ruler also provides controls for formatting text such as options to adjust style, alignment, spacing, and create numbered or bulleted lists.
To measure the distance between two objects on the page, click the Measurements tool in the Toolbar. Click and drag between objects to see the distance. Set the units in Preferences > General.
If your drawing already has units built-in, such as a drawing generated from an architectural program, then those units will be shown using the measurements tool.