Here is what I need. Can you Help me?

Here is what I need. Can you Help me?

Hello;

I need the follow to open new client.

1.In the WEB my prospect fill a form and send to me
2.We send him a mail saying we will get in touch
3.We call him to answer the questions
4.If he is still intersted, I send a email and wait him to send me information/docs.
5.After that he is a client.

What shoud I do? WEB CASE or WEB LEAD ?

And how to set up the information flow ???

How can I do it in ZOHO CRM ?