I am at the start of the game but i cant seem to be able to pick up the broken fuse from the fusebox like it says in walkthrough.

Use 2 left clicks to do the actions.
Also remeber to right click on everything also.

The first left click describes an item; the second left click gives additional information or does the action if needed on that item (take, press...). So click until the cursor is grayed out or disappears.