Looking 'round, it seems like these expressions can be written in neater ways. Might as well continue the trend.
The title is useful more than once in this puzzle. So is a good calculator, either the mechanical or human variety.
Check the floor if you don't know where to begin. Check a mirror if you're stuck halfway.
The integer part of each number translates to an instruction. Make sure you're using the shorthand here.
After following this, you'll have a new list of numbers to which the reverse of the instruction can be applied.
These new number strings correspond to letter strings that would also like to be continued...