This achievement is straightforward enough, you just need to combine some bandages or a handkerchief with an explosive bottle and the achievement will unlock, you'll find these items and a bunch more around the map from the second level onwards.
Once you've found both of the items required for this achievement press down on your D-pad to open up your item menu, use left/right on your D-pad to select one of these items, once you've selected one press "X" to combine it and then choose the other item, once the items have combined the achievement will unlock!
Lastly, it's worth taking a look here;
Solution for Handyman Carnby In Alone In The Dark (2008), as this game has an achievement for creating every possible item combination, while it doesn't specifically relate to getting this achievement, if you're looking to fully complete this game it's something you'll want to keep track of as your progress through the game!