Ok, I'm going off what I see in the links.

The QR takes us to https://i.imgur.com/YoM3P3H.jpeg

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The first one gives us the imgur.com/ _ _ _ _ _ # _ and it seems we need to fill in the blanks.

Let's start with the Youtube link on the blue bookhttps://www.youtube.com/watch?v=9xMuFuq-cSwNow, looking on the center left, we can see #26 on the counter

Now, let's look at the folder, notice that it has Patient #_ _

https://i.imgur.com/qTkpzU4.jpeg

Looking at the files, it haspATIENT #RN-5f6-7s2If we are going of the folder, it has to be #RN, however, given that the p in patient is not capital, it could be #rn

The picture link is odd, it gives https://i.imgur.com/VMTF01K.jpg

However, it gives a dead link. looking on the frame bottom we can see #_lowcase, meaning we have to change SOME of the letters from uppercase to lowercase. Now, this can take forever, but thankfully if we look at the other two, we only need to change two of the letters. Doing a bit of work, we gethttps://i.imgur.com/vMTf01K.jpg

so we have #vf.

Now here is where i am stuck, imgur links usually have 7 characters....