Welkome to Zwift,
Lets start you off on the right track. This is very helpfull reading.
http://www.titaniumgeek.com/cycling/zwift/zwift-user-manual-unofficial-running-updates/
What trainer do you have I see a Elite Qubo Fluid and Elite Qobo Power but not a Elite Qubo Power Fluid?
Now I assume you have a “non smart” trainer with a speed and cadence sensor.
Your garmin head unit and Zwift will not show the same speed, Zwift calculate your speed according to the power you produce.
Looking at the speed/power curve you should be generating about 250W at 26km/h. Is that about what you see on a flat road. this is a very crude estimation.