Good afternoon! I am new here and have little development experience. I am just looking for some direction on how to approach this issue.

I have a client that has purchased a marketing list. The list has 3100 leads and each lead has a unique code associated to it. We will be loading the list (and code) to Salesforce for the client. Once this is loaded, he is looking to do the following:

- The lead (person) is sent a mailing with the unique code (this is done automatically through another app). The lead would be directed to go to a web form to enter the code on the mailing. Once the code is entered /  submitted the lead information (name, address, etc.) from Salesforce will populate the form.

- Once the form is populated the lead will be able to either confirm (submit) the form or edit it and then submit it.

- If the lead does not have his or her code they should be able to enter their information manually

- Once submitted Salesforce will create a task for the lead owner to follow up with the lead.

- Once the lead submits the information on the webform the lead in Salesforce should flip to an prospect

I posted this question to the success community and it sounds like Web-to-lead will not fit all of the requirements for this request. Can someone point me in the correct direction to start on this project? Since web-to-lead isn't an option I was pretty sure this would be done with visualforce / apex. However, there is a whole lot of information covered in a general visualforce / apex book. What should I start with in order to create this?

Thanks so much!