Hello,

> i am new with this alternative operating system, i read the amiga install
> guide but is very confused with some things... can you help me how can
> install the 2.0 on my amiga?

It takes a bit of work to get everything set up, but it's worth the 
energy.

> i download the iso from the ftp but i dont know for execute the miniroot.fs
> and if i need to format the hd in unix filesystem or a standar...

You need to read the part of the install documentation:
ftp://ftp.NetBSD.org/pub/NetBSD/NetBSD-2.0/amiga/INSTALL.html

which talks about partitioning. You'll need to partition a disk using 
AmigaDOS' HDToolBox or something equivalent. Depending on what kind of 
SCSI or IDE bus the drive you wish to boot is on, you'll either have to 
use bootblocks or a program called runbootblocks.

Read up - if you get stuck, people on this list will help out.

John Klos