Advance in this area, taking out the relevant enemies on the way, and make your way slightly north to the next campsite.
From this campsite, make your way up the stairs to the left of the campsite, and the next Elite Enemy Golem will be at the top to defeat.
After defeating this Elite Enemy Golem, the shack just behind him will contain the next Manual, it will be for the Acid Bolts, make sure to head inside and pick this one up before leaving the area.
Head back past the nearby campsite and keep heading south to find a large rusted shack where inside will be a Manual for the Fire Arrows on the left table
Into the very final area, the location is shown below
just to the right of the campsite will be a Merchant that you will need to purchase 5 Manuals from, including; Extinguishing Sand, Bottle Of Acid, Torch, Acid Arrows and Fire Bolts.
All of the arrow & bolt schematics can be purchased from the Merchant NPC, as picture on the map below. There are 5 of them available for purchase at this location.