This section of the guide to Mr Prepper contains information on how to repair the ropeways in the forest to get to the higher levels of the area. You will also find out where to find the lever, which is one of the elements required for the repair.
The lever in Mr Prepper has only one function: it is required to fix the ropeways which allow you to get to the higher parts of the forest. Apart from the lever, you also need materials, the required quantity of which increases with each level. The first level required only the lever, though. You will find it on the next sub-level of the forest (use the paths deep into the forest to go further), near the herbalist who is hiding in the bushes.
To obtain more levers, you need to get all the way to the last stage of a given level in a given location. A boss fight awaits you there - you must fight a group of wolves at their den. Only when you defeat them can you pick up the lever, which is always somewhere nearby - although not always visible. Move the cursor over the bushes to locate it.