At this stage, you need to consult an attorney in your local area before you proceed further, as the next step is the kick-off meeting, where confidential information will be exchanged between you and your client. To protect your company and your client, you need to sign an NDA contract to protect all the exchanged information that your client will trust giving to you.

To find a sample of an NDA check your country/region laws; for example, here in Canada we have a good site LawDepot.ca that has a large choice of law contract samples depending on your province.