The trick with time series is that you just need a vector of the variables other than date.
my_ts <- ts(c(1220,2200,8800,7743,4432,56789,95643,2200,23400,3340,2098,12098,12060,10980,202987,40003,30009,3480,40090,6800,40088), start = c(2018,1,3), frequency = 52)
my_ts
#> Time Series:
#> Start = c(2018, 1)
#> End = c(2018, 21)
#> Frequency = 52
#> [1] 1220 2200 8800 7743 4432 56789 95643 2200 23400 3340
#> [11] 2098 12098 12060 10980 202987 40003 30009 3480 40090 6800
#> [21] 40088