Start a new game on Spartan Mode, difficulty does not matter. The game is very straightforward and shouldn't pose much of a challenge.
However if you do get stuck i'd advise you typing the level you are stuck on into Youtube and watch a walktrough. Alternatively here is a very thorough written guide to help you out: https://gamefaqs.gamespot.com/xboxone/824052-metro-2033-redu...
Note that you cannot stack this achievement with the Survival Mode achievement:
This means that you need to play trough the game at least twice.