[support] drupal wizard workflow

I am working on a website where users are supposed to 1. login 2. purchase a product (soft product - code )- lead them to checkout directly 3. pays - then product is emailed to them 4. exits The site is only supposed to do the above 4 steps. What would be the best way to approach this? thanks. -- Tel:254- 722-490994 www.agile.co.ke | www.jipambe.com