Hi Ghunter,

Dataflow and evaluation are different procedures.These are all step by step procedures that will help you obtain a lisence from qatar. First of all you will need to pass the prometric exam. Regarding Dataflow, it can be done by yourself without any employer.It is the verification process of your certificates,lisences and work experience. Once you have completed dataflow you can apply for evaluation but that requires an employer. Evaluation is the process by which they evaluate wether you are eligible and qualified for the post you have been hired. You can apply for dataflow even before you write prometric but prometric is surely required to complete evaluation process.

These all are long processes and its better you right away apply for dataflow and sit for prometry exam as that will increase your chance of obtaining a job here. If you are a male, try with some companies as they hire industrial nurses.
Attache below a link in which you will get more details of dataflow.
http://www.dataflowgroup.com/docs/SCH%20Qatar%20application%20how%20to%2...

Hope this will be of help....and plz dont hesitate to clear any doubts.