to converting latex to pdf file

There are mainly two ways for conversion

1) type the following commands after coding your TeX file
latex first.tex
dvipdf first

2) type the following commands after coding your TeX file (using pdflatex)
pdflatex file.tex
pdflatex can't include eps-graphics. Convert all eps Files to pdf with the command
epstopdf file.eps

To convert a landscape dvi file to landscape pdf file
1) Switch to landscape in your TeX file:
\documentclass[12pt,landscape]{article}

2) Compile with 'latex' as usual
latex

3) If you like to check with 'xdvi':
xdvi -paper a4r

4) Create Postscript/pdf:
dvips -t landscape
or dvipdf -t landscape