Finding & Downloading boot.elf files and putting it on the root of my sd card/ Nintendo Wii 4.3u?

I tried every site, downloading "boot.elf files", to install the homebrew channel for the Nintendo Wii, But, every time i extract the "boot.elf files" onto my sd card using WINRAR, the file just read "boot" on my SD card. Are the files corrupted? If so where can i find uncorrupted boot.elf files, or i'm doing something wrong! Please Help me!