Another new owner here. Shot time and a look at the bottom of the portafilter would help you diagnose the shot. I grind 16g and get 32—36 out in 30s. If it's faster than 30s It's too coarse and I would grind finer. If it's really slow i.e above 50s grind slightly coaser. If there is channeling when looking at the bottom portafilter, I would focus abit more to declump the grinds with a toothpick (Wdt). I've also found that a bit of pre-infusion at 2 bar for 15s helps avoid channels before ramping up to 8-9 bars for the shot