Hi, Bubba! The idea that you need an item to perform a particular action is left more up to the interpretation of the player. For example, if you would want to scale a wall, you could do so without any items or tools if it would make sense to you. When scaling a mountain, however, it would probably make more sense for you to use some things like a rope and hook. But, hey, maybe you envision your character as this master mountain climber that doesn't need any tools for scaling mountains.
Since a huge part of solo roleplaying is about player imagination and interpretation, I wanted to leave this particular rule open to that idea. For me, I imagine how a player would tell a DM they want to do something. The DM would then decide if the action requires an item to perform it (for example, taking a sample of water would require a receptacle of some kind for storing it).
To sort of reward more creative thinking, there exists an optional 'Item Bonus' rule for when the player determines an object would be needed to perform an action. I pasted the rules covered in that section for you below (you can also find it on page 31 of the latest version).
As an optional rule, you may decide that using one or more items when resolving a skill test grants +1 to your roll (this rule does not apply to attacks made in combat). While this gives items an even greater utility, it also makes the game somewhat easier.
I hope that clears it up a bit, but, if not, feel free to ask further questions any time.