trying to get gear4...

I've been trying. It lights up with a blue arrow when I get near it...how do I actually get it tho????

I have weights and gear one in my inventory...confused.

Did you find out how? That's exactly what I'm stuck on!

To get gear 4. There are 3 sites open which you need to go to each site, find hidden objects and weights go on one of these sites, where you find key to open area where 4th gear is. I hope this makes sense.