Find a shop hopefully close to you that has a fit bike. You shouldn’t buy a bike before the fit. If they are trying to fit you to a bike they are doing it wrong. They should get the fit and then determine which bikes work. This may not be a bike they stock.

Also ask for fit pictures of previous people and determine if they actually look like they know what they are doing. I.e they look closer to pro TT riders and further away from mountain bikers. We’ve seen some brutal fits over the years from actual fitters. So don’t just assume they know what they are doing.

When starting from scratch without an existing bike and fit the best approach is usually an independent bike fitter. They don't have any motivation to sell you a particular brand or sell you something in stock. Before scheduling and attending a fit session be sure the fitter will be providing you a final fit sheet that can be translated to any bike (contact points by X,Y) along with some options for bikes/aerobar system combos that will work for your fit.

One of the biggest issues with fits seem to be saddle selection. The type and model of saddle used for your fit needs to be used for your bike build.

You can peruse the ST Bike Fitter Database to see fitter options in your area. As mentioned above, fitters still can yield bad fits, so it is always best if you can get first hand feedback from clients regarding fitters. After seeing a fitter you can come back to ST with any additional questions ahead of committing to a bike purchase.

To narrow things down on bike selection you should have a good idea of your budget. Unless you are an outlier w/r to body morphology there will likely be a number of bike options available to fit you. I'd suggest you buy a brand and model of bike that allows ordering parts and receiving service from a LBS.