My stationary bike has a display that tracks loads of stuff but there's also a phone/tablet holder if you prefer an app. You can use anything you want but you just gotta commit to a certain run plan.

As for me, I do about 10 minutes at low resistance, high pace. My dash shows me a virtual speed indication. I do the first 10 minutes around 25 kph.

Then I slowly move through the gears and try to keep the pace flat. After 25 minutes I do a short intermission where I get the lowest gear and paddle loose the legs.

Then the buildup again and trying to keep the pace above the previous pace.

Essentially it's all about what you want to gain.

For strength, you'll do better with explosive bouts (after proper warmup or you'll tear off your leg muscles). For endurance, it's all about keeping up a pace in intervals. The higher the pace you can consistently keep during a set time period (for instance an hour), the better, but it's important to find your base level first by taking it easy. Consistency is key above all else.

Keep in mind that if endurance is your goal, you should never think 'oh this is going pretty easy, I can take it up a notch' because you might not last the full hour without over exerting yourself which will lead to sore muscles. The other way around is also true, though: don't give up if it gets tough. But there's a difference between stretching your comfort zone and going outside the lines.