At least you gave it more than one try. As a quick rundown, the items are generally not meant to be necessary but simply minor additions to the gameplay. For most items, simply left click to use them and you can use the inspect to figure out what they do(Although the repair kit is a bit useless). Items like the upgraded lamp and especially the axe can make the game much easier, but are as a result quite expensive to get and take some time to gather all the resources. Until you get those, it is a game largely about trying to evade enemies and most, especially the later ones, have unique weaknesses and mechanics which you can use to better evade them. Thank you for playing our game!
Sincerely,
Henry_Hamster.