If you want to 'Show Only' a certain 'path through the map. IE the items before an item that contribute to it and those after that it contributes to, Use the Show Only feature.

This hides the other links and 'ghosts' out the other items that are not on the path. 

This is great to simplify a complex map and allow discussion of what is most important.

If you select an item on the map and then right-click you will see on the menu the option to Show Only, then you can select only that item with This or other options like Before and After.

You can then click around the map seeing only the links for the items that you select.

Then when you have finished click on Show Only >Everything to revert to the standard view.