I’m guessing this has been covered a bunch already, but I haven’t been able to figure out what to do by reading other responses (my apologies if I’m retreading here). I normally ride about 16 mph on flat ground on my road bike and 18-19 on my tri bike on the same flat ground. I’ve no clue about power output normally. New to Zwift and my speeds on virtual flat ground are about 10-12 mph and uphill at about 2-3 mph. Walking avatars are passing me. But the aggravating thing is EVERY other bike passes me and I can’t even begin to participate in any virtual group ride. I try to maintain a cadence of around 90 like I normally do and use my cycleops supermagneto pro at level 2 like the instructions state. Is there a way to make this more realistic with my dumb trainer?
Tell us more about your trainer etc…
I’m wondering if its a calibration issue. Have you calibrated your trainer?
On the pairing screen you’ll see a 
icon.
Welcome to the forum.
Try riding the tempus fugit route in Watopia. It is a nice flat route to test.
Zwift primarily bases speed off of power output / height / weight.
Check your trainer / power meter is set up and calibrated correctly (check youtube etc.), check your height/weight details are accurate, and if anything you should be a little bit faster on Zwift than in real life as it is assuming you are on a top-tier bike with optimal body positioning which is often not the case IRL 
It could be that the power curve Zwift has for this trainer is too low.
OK, what kind of power is Zwift reporting when you are on flat ground and making the same kind of effort as you do outdoors? Also, is your weight and height set correctly?
My height and weight is set correctly, as is my tire diameter. I’m not sure how to calibrate a dumb trainer, but all I did was pick the trainer that I have from my menu and used setting 2 like the instructions said to. If my memory is correct, it reported something like 70-100 watts on flat ground (probably averaging somewhere around 85) when compared to a similar outdoor effort.
I’m not sure how to calibrate my trainer (it is a dumb trainer with no adjustments). However, it is listed as one of the supported trainers but the issue is the speeds are not close to actual speeds I ride.
I will try - but I also tried short (less than 5 minutes) on a couple of flat courses and I would run about 8-12 mph, less than I average outdoors.
I’ve read that too, but my experience is the opposite. I don’t really care what the actually speed is (I’m still getting a workout), but it sort of ruins the whole thing when you can’t keep up with ANY other riders and people pass you walking along the side of the road!
Is setting 2 showen on the pairing screen?
Are you sure you have the speed sensor on the wheel? Sometimes they are flipped so the speed sensor read the cadence.
Try only connecting the speed sensor
Thanks for the suggestions. I’ll try but they are connected correctly and the RPM reading is correct on the screen matching the actual crank rpm. The setting two is given “use setting two” when I pair with the trainer.
How many watts is Zwift reporting when you’re pedalling reasonably hard?