First you'll need to find a radioactive spider and get it really mad at you by poking at it with a stick. After it's good and ticked off switch the stick for the middle finger on your right hand(use left hand if left-handed)and let it bite you being careful not to pull away so as to let it inject all of it's venom. Also take care to NOT let the other hand smash the spider and end the process. After the spider removes it's fangs from your finger raise your hand above your head to let the venom drain into your body. Now just sit back and wait for the transformation that will surely take place. Soon after the changing you will have all the knowledge of the spider and the secret of the web will be revealed to you.
Good luck you little spiderman you!