First of all a emergency services should be called to get to the hospital. After calling you need to wait till the emergency reach to you. Till then you can give the patient some first aid written below-

1- Keep checking if the patient is breathing or not. If patient don't breath then you have to perform Cardiopulmonary Resuscitation(cpr)

2- Try to keep the patient warm in anyway.

3- At the time of stroke you may not give them anything to eat or drink even if they are dying for it.

4- Keep talking with emergency service and tell them every symptoms for suggestion of better first aid.

5- Don't move the patient too much, if he/she become weak.

6- Keep calm and maintain everything smartly. Hurry may bring disaster.