on the left border on your web page, click on "RULE" and "HOW TO SOLVE" - that'll give you the most basic information about the puzzle.
For techniques to help you other than what's presented here, go
here and
here - they have very good explanations, examples and diagrams.
And if you get stuck anywhere, post the puzzle you're working on (the numbers you already have filled in, and then another grid with the candidates you have remaining, if you're using candidates - check other posts to see the most readable formats) in the
Help With Particular Puzzles forum, and someone will be able to assist with your next step.