Advice on buying a house..

Ok soo my partner and I have been wanting to buy a house over a year. We been looking houses for sale on apps like Trulia, Zillow etc. Recently there was a house we both liked the price was high but we would negotiate with the seller right, but someone already bought the house.it was a bummer for us, bcuz we really liked it. He was pre-approved for a mortgage loan, he can also give a very good downpayment for any house thats with the budget we want. We are looking for a 3bedroom house, with backyard for our childrens. Im pregnant and we are hoping we can buy something bfore baby arrives in Dec. He also spoke with a real estate agent over the phone about what we are looking for, but since the talk we havent recieved any call from him. I would like to know how was the process for any one who became first time home buyers?? What steps?? Who to call?? What to expect?? Do i need to pay a real estate agent?? Any advice, or opinions i will really appreciate. What is it to look for?? I know we can do it, i just dont know how to start the step we are in is the mortgage loan and looking through houses on apps.I just want us to have a home, bcuz the apartment we are at its too crowded. Thanks.