Hello Samantha. What you need to do Samantha is get yourself a set of Shimano SPD Mt Bike/Touring cleats. There are a couple of different models but they will all fit any pedal that is Shimano SPD compatible. Most bikes that have even there own clipless branded pedal will still work with a Shimano cleat. Keiser (I agree with the groan) use genuine Shimano pedals so thats all good too. Any bike shop with an ounce of know how will have them in stock. Get the shop to help you fit them in the correct position on your shoes.
Have fun and just watch your indoor cycling improve.
Lee
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Food is Fuel.