Error while converting netcdf data into a raster brick - r

Question

I'm trying to visualize monthly averages of RegCM output I joined using CDO but I'm not being able to do it.
In order to do that I was trying to find a way to plot de monthly averages of my variable "pr" as you could do using GrADS.
I found that a way to do this was using the brick function and the raster library. So I was trying to use the code suggested in another question to convert my netcdf file into a raster brick:
NetCDF to Raster Brick "Unable to find inherited method for function 'brick' for 'ncdf4'"
# load package
library(sp)
library(raster)
library(ncdf4)
# read ncdf file
nc<-nc_open('dat.nc')
# extract variable name, size and dimension
v <- nc$var[[1]]
size <- v$varsize
dims <- v$ndims
nt <- size[dims] # length of time dimension
lat <- nc$dim$xlat$vals # latitude position
lon <- nc$dim$xlong$vals # longitude position
# read pr variable
r<-list()
for (i in 1:nt) {
start <- rep(1,dims) # begin with start=(1,1,...,1)
start[dims] <- i # change to start=(1,1,...,i) to read timestep i
count <- size # begin with count=(nx,ny,...,nt), reads entire var
count[dims] <- 1 # change to count=(nx,ny,...,1) to read 1 tstep
dt<-ncvar_get(nc, varid = 'pr', start = start, count = count)
# convert to raster
r[i]<-raster(dt)
}
# create layer stack with time dimension
r<-stack(r)
# transpose the raster to have correct orientation
rt<-t(r)
extent(rt)<-extent(c(range(lon), range(lat)))
# plot the result
spplot(rt)
But once I tried to run the for loop in the code, I get the following error:
Error in ncvar_get_inner(ncid2use, varid2use, nc$var[[li]]$missval, addOffset, :
Error: variable has 3 dims, but start has 2 entries. They must match!
The file I'm trying to visualize can be found in the following link:
https://drive.google.com/file/d/13KsOpnt-Wk2v93WwGcOU6AHw8KGOFlai/view?usp=sharing
I would really appreciate any insights with this problem!