How do I know how much house I can afford?
In general a home should not cost more then 2 1/2 times your annual income and the mortgage payments should not exceed 25% of your monthly income. Other financial obligations can alter these suggestions.
Remember that a larger down payment will help keep the monthly payment low enabling you to qualify for more home.

I do not know how to look at a home, I am not a carpenter?
You should have plenty of time to review the home. You may even want to take a second look. It is the largest single investment you will probably make so do it carefully. When in doubt, hire a professional. You can have the home inspected or if the home is older, ask the owner to split the costs of inspections with you. A home inspection for utilities and electric are normally very reasonable.