You need to be more specific. Assuming you are referring to putting a PayPal item button on your web page, i.e., a Buy Now button, Add to Cart button, Donation or Subscription button, you can find some very useful information here. Suggest also checking out the Training Library, there you can find some informative tutorials.
For basics, PayPal has an online button creator that can generate code for you. You choose the type of button you need, complete the necessary fields, generate the code, copy it and then paste the code in your web page. You can find the online button creator by logging to your Account, select the Profile link, under Selling Preferences, select Create New Button.
Regards,
skier
