[R] Understanding how R works

[Alaios]

Hello everyone.
I am more than new into R.
Today I have started reading about  grf function that is included in geoR 
package. 

According the manual (vignette?)


grf() generates (unconditional) simulations of Gaussian random fields for given 
covariance parameters. geoR2RF converts model specification used by geoR to the 
correponding one in RandomFields.

I would like to use this function to fill in with valies a rasterlayer.

According to the manual grf() returns a list

Value
grf returns a list with the components: 
coords   an n x 2 matrix with the coordinates of the simulated data. 
  data   a vector (if nsim = 1) or a matrix with the simulated values. For the 
latter each column corresponds to one simulation. 

  cov.model   a string with the name of the correlation function. 
  nugget   the value of the nugget parameter.
  cov.pars   a vector with the values of sigma^2 and phi, respectively. 
  kappa   value of the parameter kappa. 
  lambda   value of the Box-Cox transformation parameter lambda. 
  aniso.pars   a vector with values of the anisotropy parameters, if provided in 
the function call. 

  method   a string with the name of the simulation method used.
  sim.dim   a string "1d" or "2d" indicating the spatial dimension of the 
simulation.
  .Random.seed   the random seed by the time the function was called. 
  messages   messages produced by the function describing the simulation. 
  call   the function call. 
  geoR2grf returns a list with the components: 
model  RandomFields name of the correlation model
  param  RandomFields parameter vector


And this is exactly the point I do not get.
In the example section of the same function I can find the following:

sim1 <- grf(100, cov.pars = c(1, .25))
# a display of simulated locations and values
points(sim1)

How the function points() understand what to read exactly from the list?

I would like tot hank you in advance for your replies
Best Regards
Alex