To help us help you, could you please prepare a reproducible example (reprex) illustrating your issue? Please have a look at this guide, to see how to create one:
This exercise appears to be about a bike-share system, not a cyclist (bicycle?) store. The dataset probably has a station_start and station_end for each ride. A reprex with a minimal dataset will clear this up.
What do you mean by the top three variables? My guess is that you want the top three stations based on the number of rides that start there. A station is not a variable.
The count() function will report just one value for each group. I think you want to create a new column in your data set instead. Look at the following reprex using the mtcars data set and compare the code and the three outputs. Also note the proper use of the pipe operator.