title explains it all, I have 3 texture packs in the texture pack file and only one will show up, how do I fix this?
If you've downloaded packs that aren't showing up in the list then I suggest just deleting them. The most likely cause is that the pack author didn't author the pack properly. Generally that means they're inexperienced, have stolen textures from other packs, or just not all that good at making packs. Often all of the above.
However it's also possible that the pack contains a virus. See, normally viruses can't infect a computer from within a .zip file. They require the user to open the file in order to be an attack vector. Minecraft protects you from this by only reading the files that it's expecting to be there so no malicious code can seep out even if it's present. But if a pack isn't working as normal, it could be because there's malicious intent afoot and the only way to fix it is to first unzip it... which then makes you vulnerable.
So again, it's best just to delete packs like that. If the author is on the forum then leave that person a message saying that they need to fix their pack. Don't let them talk you into unzipping it, as the burden make a pack work properly is on the author not the user.
I also suggest only downloading packs from a reputable source like CurseForge since those are all checked for viruses and for proper functioning. Inversely, Youtube is the worst place to get packs from for a lot of reasons.
I hope that helps you.
But if you're really, REALLY sure you want to do this what you'll need to do is extract the files from the pack. Look for a folder named "assets" and two files called "pack.png" and "pack.mcmeta". Create a new, empty .zip file and drag those things into it. You should immediately see them when opening the new .zip file. You should NOT have to click on another folder within the .zip file to see them. This is the newb mistake that a lot of inexperienced or low-quality pack authors make.