RMP package files

[Instant]

I downloaded an RMP package file...
how can I install it?

I tired
sudo apt-get install rpm
then
sudo rpm -i /home/user/Desktop/lazarus-0.9.22-0.i386.rpm

I got many errors:
error: Failed dependencies:
/bin/bash is needed by lazarus-0.9.22-0.i386
/bin/sh is needed by lazarus-0.9.22-0.i386
/usr/bin/env is needed by lazarus-0.9.22-0.i386
/usr/bin/make is needed by lazarus-0.9.22-0.i386
desktop-file-utils is needed by lazarus-0.9.22-0.i386
fpc = 2.0.4-0 is needed by lazarus-0.9.22-0.i386
fpc-src = 2.0.4 is needed by lazarus-0.9.22-0.i386
gdb is needed by lazarus-0.9.22-0.i386
gdk-pixbuf is needed by lazarus-0.9.22-0.i386
glibc is needed by lazarus-0.9.22-0.i386
gtk+ is needed by lazarus-0.9.22-0.i386
libX11.so.6 is needed by lazarus-0.9.22-0.i386
libXext.so.6 is needed by lazarus-0.9.22-0.i386
libXi.so.6 is needed by lazarus-0.9.22-0.i386
libc.so.6 is needed by lazarus-0.9.22-0.i386
libc.so.6(GLIBC_2.0) is needed by lazarus-0.9.22-0.i386
libc.so.6(GLIBC_2.1) is needed by lazarus-0.9.22-0.i386
libc.so.6(GLIBC_2.2) is needed by lazarus-0.9.22-0.i386
libcrypt.so.1 is needed by lazarus-0.9.22-0.i386
libdl.so.2 is needed by lazarus-0.9.22-0.i386
libdl.so.2(GLIBC_2.0) is needed by lazarus-0.9.22-0.i386
libdl.so.2(GLIBC_2.1) is needed by lazarus-0.9.22-0.i386
libgdk-1.2.so.0 is needed by lazarus-0.9.22-0.i386
libgdk_pixbuf.so.2 is needed by lazarus-0.9.22-0.i386
libglib-1.2.so.0 is needed by lazarus-0.9.22-0.i386
libgtk-1.2.so.0 is needed by lazarus-0.9.22-0.i386
libm.so.6 is needed by lazarus-0.9.22-0.i386
libpthread.so.0 is needed by lazarus-0.9.22-0.i386
libpthread.so.0(GLIBC_2.0) is needed by lazarus-0.9.22-0.i386
libpthread.so.0(GLIBC_2.1) is needed by lazarus-0.9.22-0.i386
librt.so.1 is needed by lazarus-0.9.22-0.i386
perl(Cwd) is needed by lazarus-0.9.22-0.i386
perl(Getopt::Std) is needed by lazarus-0.9.22-0.i386
perl(vars) is needed by lazarus-0.9.22-0.i386
how can I install it?

[devils casper]

* Ubuntu is Debian based and does not support packages in .rpm format. convert .rpm packages to .deb with alien. alien is available in sources.
* apt-get downloads and install packages from sources only. Install already downloaded packages with 'dpkg' command.

sudo dpkg -i <package_name>

most of packages are available in sources. i would suggest you to install packages through apt-get or Synaptic only.
open Synaptic, type package_name in Search box and install it.
or

sudo apt-get install <package_name>

check this Tutorial : How to Install Softwares in Linux?

[Instant]

so to install .rpm I should change it to .deb
I downloaded Alien but I have no idea how to use it ....
please help

[devils casper]

alien -k <rpm_package>

it will convert .rpm to .deb format.
install .deb package with dpkg command.

sudo dpkg -i <.deb_package>