Permissions in this section activate the Leads tab and grant access to the various buttons found at the top of a Lead Record.
Mouse over each Permissions listed on the left side of the screen and a small pop up window will display a brief description of what each item does.
Do you want your Sales Reps to have access to any of the items in this section? If not, move onto the Reports section. If yes, then use the checkboxes on the right to assign the applicable level of access (View, Create, Modify, Delete, or Yes).