Removing motherboard to replace fan

Hello ifixit community,

I have owned an Asus K455LD Laptop for 2 years, and recently the fan became rather noisy, so I bought a replacement.

I was under the assumption I could just remove the keyboard cover, loosen the screws on the fan and replace it, but after receiving the part and trying it out today I found that I would have to at least remove the motherboard. How do I do that? Are there any guides? My own, long searches have found none so far.

I tried removing all visible screws, but it did not come off and I didn't want to use force.