The answer to your question depends on how much detail you require to be an adequate explanation, but please consider the following possible answers to your question (in increasing level of detail):

1. A prion is a misfolded protein (which you know) that also exists in a correctly folded conformation in the host. When a prion comes into contact with such proteins, it acts as a template to induce a conformation change in the host protein resulting in it assuming the misfolded conformation. These changes then progress in a catalytic like manner resulting in massive changes in conformation with a resulting toxic effect on the host.
2. In somewhat more detail, please see the link below, which provides a brief, more more detailed review of the subject (along with the effects of protein folding in other disease states). Scroll down to the middle to read the portion specific to prions.
3. I could not locate an adequate scholarly review article by searching pubmed, but I did find many articles about specific aspects of the process, possibly in more detail than you'd like. You might be interested in reviewing some of them, in which case I suggest searching for the following in your browser (including quotes): "review prion template conformational change native protein pubmed".

Link for item #2: https://chem.libretexts.org/Courses/University\_of\_Arkansas\_Little\_Rock/CHEM\_4320\_5320%3A\_Biochemistry\_1/02%3A\_\_Protein\_Structure/2.4%3A\_Protein\_Folding\_and\_Prions

I hope that this helps.

The first thing to understand is that prions are a specific protein (prp) that can only misfold other, properly folded versions of that specific protein. Since this particular protein is rare in most tissues, prions don't generally have a big effect outside of nervous tissue.

The second thing to understand is that prions misfold each regular PRP by sticking to them. See this image for example. Regular prp sticks to prions, forming long chains of prion proteins all stuck together. Those break (or are broken) apart and more proteins stick on the end.

So, generally, the 3d configuration of a protein is determined by the interaction between different segments of the protein and the aqueous solution of the cell. Hydrophobic sections of the proteins structure stick together to reduce its contact with the aqueous cytoplasm, while the hydrophilic segments gravitate towards the outer surface of the protein aggregate.

Now, generally, prions occur when a misfolded protein instead has the hydrophobic segments on the outside of the protein aggregate, making the protein insoluble in the cytoplasm. These misfolded proteins not only "clog up" cells and tissues, but, in the case of prions, causes their other properly folded counterparts to misfold; as the properly folded protein comes near the hydrophobic aggregate, their own hydrophobic segments are drawn to the surface and the protein falls out of solution becoming a prion.

When a prion touches its protein version, it induces the protein to convert into a prion in a process similar to how enzymes in your body break down proteins or manufacture proteins in a catalytic reaction.

This does not change the original prion, which means there are 2 prions now, and they can convert proteins twice as fast.

And then it cascades from there and all the proteins in your body eventually become prions.

The reason why this occurs is that prions are usually the “better” shape. Proteins are held together by many different chemical bonds, and some of these bonds are not entirely stable. This is because in order to do their jobs, enzymes usually need to have “active sites” that have relatively unstable bonds that allow them to bind to their substrate.

Because prions are more stable than their protein counterpart, they induce the protein to change into the prion, because that way it will become more stable.

This is also why prions are so difficult to get rid of, their new conformation is the most stable, and can withstand much more extreme environments than the original protein.