You can always use SimBrief for free at first and get a subscription for Navigraph at a future point. I had some issues setting my Throttle as well, but a little research, youtube and trial-and-error got ot solved - now it works after a complete reset and recalibration. The default flightplan setup at the start of the sim doesn’t enter anything, you’ll need to either download it via the FMC (Fenix A320) or manually enter - but that’s not as difficult as it may seem at first. Patience is the secret ingredient to get this working.
Feel free to ask questions, I’m sure the community will gladly help you. But, the first step is on you. All the best.
Kind regards.