First I would like to Congrates you, That will be a dream for all of us to buy a house.
I would happy to help you with this.
You have to consider these point:
1. Facing of the house should be North or East.
2. Check Brahmasthan of the house , it should be empty.
3. Toilet should be in North West zone.
4. Kitchen should be in South East of the House.
5. Master Bedroom should be in South West.
6. Childrens room should be in North East.
7. Stairs should be in North west of the House.
8. Main door should be in North or East side.
I hope with these points you will know about what to check about a new house.
for details you can read our Vastu for House article.