If you create multiple v6.x forms on a task you need to add "Next" and "Previous" widgets to allow navigation between the different forms. You should add one submit button on the last form.
Also I would rely recommend to use v7 forms as they includes tons of improvements (especially related to dynamically display/hide content) and also will be supported for a longer time frame.
Please avoid to post a comment such as "please, i need help !!!" (I think this Stack Overflow comment rely explain why). If time is key for your project I always recommend to consider getting in touch with Bonitasoft for consulting.