Expanding on this just a bit. You need to bind the result of summarize() to a name, so that you can use it again. Your result will be the same, but you'll be able to access it to continue your work.
I have the same code twice, below. The first time, it prints, but I didn't actually give it a name, so I don't have a way to access it again. The second time is exactly the same as the first, except I give it a name, mt_summary. The result doesn't print like it does the first time. If I want to see it, I just call it by its name again.
library(dplyr)
# not bound to a name
mtcars %>%
group_by(cyl) %>%
summarise(mean = mean(disp), n = n())
#> # A tibble: 3 x 3
#> cyl mean n
#> <dbl> <dbl> <int>
#> 1 4 105. 11
#> 2 6 183. 7
#> 3 8 353. 14
# bound to a name
mt_summary <- mtcars %>%
group_by(cyl) %>%
summarise(mean = mean(disp), n = n())
mt_summary
#> # A tibble: 3 x 3
#> cyl mean n
#> <dbl> <dbl> <int>
#> 1 4 105. 11
#> 2 6 183. 7
#> 3 8 353. 14
Created on 2019-09-13 by the reprex package (v0.3.0)