Simple, visit medical commission ( near medical R/B)between morning 7am-2pm or evening 3pm-6pm, with the copy of visa and original passport of your family, child no need medical checkup but you have to pay for them, go to the family gate and sent your wife with above docs and your debit card. if less crowd within 1 hr, your work will be done. Each will cost QR 100. if your registered at Metrash , you will get sms of the result less then 3 days. Cheers.