Tomb Raider I-III Remastered Starring Lara Croft

This can easily be done in the first level "Caves". There are a total of 7 medipacks in this level.
3 of the medipacks are hidden secrets, whereas the other 4 can be found placed throughout the level.
You will unlock this achievement once you've finished the level and have collected all medipacks.

This level map below will help define where each medipack can be found, it should prove helpful:



This map in question was found on Stella's Tomb Raider site, feel free to check the site out for more walkthroughs on the Tomb Raider series: https://tombraiders.net/