Only registered users may apply for posted jobs. You can use the following methods to apply for a job:

1. click on the Apply for this job link at the bottom of the job page. This will automatically inform the recruiter via e-mail that you have expressed an interest in the job. It is then up the recruiter to contact you either via the site or directly. The recruiter will be able to track your job application in his own Job applications screen, see My Baanboard > My Job Applications.
2. reply to the job posting via the Add comment option at the bottom of the job page.
3. use the contact details specified in the job posting to directly contact the recruiter (i.e. via e-mail, phone, ...)