From The Document Foundation Wiki
How do I place a grid in the background to use as a guide?
If the grid is not currently visible, you can do any of the following:
- right click at the bottom of the page,, then on ▸ ;
- select the ▸ ▸ menu;
- select the Options toolbar( ▸ ▸ ), then click on the second button Display Grid.
This last toolbar provides access to almost all the grid options. The grid spacing is set by the▸ ▸ ▸ ▸ menu.