You can create lines on the document to use as guides for your boxes. (If you want the guides on all pages in the same position, create the lines on the master page)
- Click on the ruler (at the top and the left of the window)
- Drag over your document
- Then let go
You can add as many lines as you want and change their position with click and drag later (If you don’t accidentally want to move the line, add a layer and lock the layer with the guide lines on it). They will not show up in your exported document.
Other InDesign tutorials: