I'm a home mortgage processor. Maybe I can help.
The first step is to know exactly what you're looking for. Getting a preapproval is key to knowing you can get the loan in the first place. They will run the numbers and tell you what you can afford based on income, tax returns, liabilities, and credit history. The pre-approval is done using a desktop underwriter or DU. It's a program that calculates risk and tells you whether or not the lender will loan you the money given the circumstances. Then to find a realtor who has a good reputation, and make sure you know how much his/her office charges and if it's in your budget. Let them know exactly what you want, size, area, taxes, condition, etc. They will pull up all the MLS results for properties matching your criteria and show you the listings. When you find a home you like, you can apply for a loan with a mortgage company, broker shop, or bank. Realtors will often suggest using their lenders, because it makes the process run smoother.
A typical approval takes about a week after you supply the mortgage company with all the necessary documentation for the type of loan that best fits your needs. After you are approved for the loan amount you are trying get, you can place an offer on the house and open escrow if the offer or counteroffer is accepted. In my company, loans usually close within 30 days, and escrow usually the same if not a little more. Once escrow is closed and you have signed the paperwork and the title is transferred to you, you can move in.
Hope that helps. Best to consult a certified Realtor. Not just a real estate agent.