Can anyone help me? I need to know how to install them properly.

Can you explain step-by-step what you're doing?

I use PeaZip to import the neighborhood into the neighborhoods folder and if needed i rename it to N and then 3 numbers afterwards

I'm not sure what PeaZip is, or anything about renaming neighbourhood folders so I'm probably not the best person to help.

I hear that you can't just rename neighbourhood folders though, this might be helpful:
http://www.simbology.com/smf/index.php?topic=7669.0
Although I don't really think it's necessary to rename folders, unless you have multiple of say 'N003'.

I meant rename it if it said "Iceland Powder Falls" I would rename it "N123" for example.

You need to look in the folders of "Iceland Powder Falls" and cut and paste the hood folder from in there not rename the folder called "Iceland Powder Falls".

When a hood gets zip/rar up the hood maker names it what the hood is called and the hood folder will be in that.

Yeah that's what I mean. I'm pretty sure that's what the link I provided is explaining?

You can't just rename it a random'Nxxx' number - well, you can, but that's not enough. You also need to rename every file that also references the original N number in the folder. You can download a program that will do this for you, which is way easier and quicker than trying to do it manually. Google 'Bulk File Renamer' or something like that. There's several programs out there that will do this. You really only need to do this if you already have a hood with the same number, though.

If you just want to change the actual name of the hood (like if it's called Iceland Powder Falls and you want to change it to, let's say, Iceland Valley or whatever) you don't need to change the Nxxx number at all, just unzip the file into your Neighbourhoods folder and load the game up, you can change the hood name on the screen when it's loaded.

All this renumber thing is not needed here, the OP needs to take out the hood folder from the name folder so it will show up in OP's game.