Picked up this Klein Pulse Race mtb bike today. I was big into bmx in the 90s but don’t know much about mountain bikes. Could use some input.

I searched the history of Klein bikes and it’s quite colorful. They seemed to be the innovator of their era. I wanted something vintage with old skool aesthetic and riding dynamics.

I picked up this bike to just ride around the neighborhood for leisure and would like to have it converted to a single speed. Any input on how much I can expect to pay for that. What parts/components and gearing would be idea?

I plan to ride mostly flats and some mild hills. Thanks for any help.