First time taking task would be separating apart pallet from pallet boards. After getting them separated choose the three planks for a DIY pallet wall shelf dimension and give them desired cuts with hand saw or other sharp one in modern and electrical form. You should have a stock of a hand drill, measuring tape, and about 2 inches screws for get together joining and assembly of all parts to be looked like a shelf.
Go with measurement of wall area and size of plank at the same time to avoid time wasting and for more high precision value in handwork. You can prepare three same sizes of these shelves to be looked great on wall and better storage option as we have done. Same technique will be used and would be beneficial while trying some other DIY pallet rack, DIY pallet book counter and other wall mantelpieces projects.