you are lucky my friend because we just figure it out. can you imagine that we've been through hell understanding people in the front desks and we got the exact procedure not from NHA (can you believe this) but in instead in some reputable company. the problem is in NHA there are no steps on how these licensing works. and some of the companies here are not aware baoput this new procedures. so stupid right!. anyway. i want to help you. here it goes.

1. Go to NHA (if your brother is here in visiting visa)
working hours 8am-11am only and go to window 11(medical licensing window) and fill up the application forms given

2. Prepare 2 sets of complete credentials/certificate/passport/cv/etc and attache it to the forms
a)the first set is for the verification of your credentials/certificates and etc. (this will take more than a month, your papers should be approved- this means your papers are authentic) you need this certification for you to present this to the employers when you apply here in qatar. you can follow up this application by email just get the email address there and you will pay 600 riyals

b) the second set you will pass this for you exam application together with the forms given. an this should be arranged according from the given requirements (like doing it alphabeticaly) you will file it in a plastic folder can be transparent and label each documents. (this should be done by nha so funny you have to arrange it for them)haha this is true!

3)but!!! you cannot pass your second set of application for your exam if you donot have the "potential employer letter"

4) so this means after applying your verification of papers,
wait and when approved look for a job vacancies. when that empoyer hires you! you will be given the "potential employer letter" or " Endorsement letter" that will make your application for exam complete. when complete
go back to nha and pass the second set.

5) and now afterall this, wait for your scheduled exam and it depends if your company wants you to work before or after the exam.

6) BUT if you are lucky and if you have a good employer. when you are hired. they can process your application for you to schedule your exam earlier.

so.. now we just found out that you cannot have nha license if you are not hired. and the stupid thing about this some emoployers here dont entertain applicants withiout nha license. so NHA should announce it!
hope you learned somthing and goodluck