Basically numbers indicate the intervals to be played above the bass. Here sharps or crossed numbers mean sharp notes on the keyboard.
Here is PDF file for printing and MIDI file for listening.
Practice this setting and try to achieve the fluency in notes, rhythms, and articulate legato 3 times in a row. Also focus on the meter and emphasize the strong beats of the measure.
NOTE: the bass part could be played with the pedals. In this case, one option would be to use full Principal chorus (Organo Pleno registration) with mixtures and Posaune 16' in the bass.