after you download muttng, tar zxvf
Next you wanna see the options you need to configure the box with... so type:
This will show you all the config options, now, I had to compile mine with imap support and with ssl support so I used...
./configure --with-imap --with-ssl --enable-hcache
After that gets done: make install
It will installl the Muttngrc file in /usr/local/etc
Go there and edit that to your config. If you need help doing that, go to the mutt-ng website and download the pdf, read.