users accounts and rights

[Clovis Sena/Servicos Recife <csena@itautec-philco.com.br>]

Hi all, 

I'm instaling a Debian Linux server and need informations about users.
I've created the users but did not understand some things. Need  some
explanation about users rights. Could some send me some help??

Also i need to know how this users will gonna login to my machine, i
mean the clients when using pcs with win95 or others linux as
workstations; I tested the server using a win95, via telnet, but wanna
know what are the clients most used by all .

thanks in advance!