How to place a memory module back into inspiron 1420

Usually the memory space where the memory module goes is on the back bottom of the laptop. There are either two memory slots there, or if not and your Dell 1420's specifications says that it ahs 2 memory slots, then the second slot is probably, most likely under the keyboard. If I were you, I would check those places and see. Once you locate them, inserting the memory is easy; you just insert it in the slot and make sure the little lock clips, one on each side, are in place in the little side grooves on the memory module. I hope this helps you out!