You appear to be entirely premature in looking at houses. Normally, when you submit an offer on a property, you include a check (usually 1% of purchase price, but can be more), and if the offer is accepted, it is held in escrow as part of the down payment to be transferred to seller at closing.
To apply for a mortgage, the lender wants to see a history of consistent savings from your earnings, not just a few months. And while 3.5% may be the legal minimum down payment, this is totally insufficient in today's mortgage market. Most lenders want to see 20% cash down, plus closing costs, plus 3-6 (some lenders now want 6-12) months of reserves. Deals with less than 20% down have to pay PMI, and that's expensive. Also, there is an inordinate number of deals which develop "last-minute glitches" and remain unfunded at closing if there is less than 20% down. This is a costly disaster for a home buyer! Also, for your own protection, anything less than 20% leaves you vulnerable to ending up underwater in your mortgage very quickly if housing prices continue to fall. It is in YOUR best interest to have 20% down.
If you do not even have 3.5% down payment saved up, you are not ready to start looking at properties. You don't have closing costs. You don't even have the money to pay mortgage application fees and all your other expenses! Seller-paid closing costs do NOT - and cannot - include your direct personal expenses such as mortgage application fees & your first year of homeowners insurance, or your prorata portion of property taxes and other settlement costs at closing since these are monies you owe the seller. Then you have your moving costs to consider, possibly deposits on your utilities plus turn-on fees, etc.
You have nowhere near enough money yet, and won't for several months, even if you can find a lender who will actually write a mortgage with only 3.5% down. And you'd pay through the nose on higher interest rate, PMI, escrow fees, and more.