Extreme Value Analysis - how to use the R package extRemes

I am completely new to R and I desire to analyse two different time series of temperature and precipitation with the R package extRemes.

In particular I desire to apply the GPD to the time series but I do not know how to use the software.

My goal is to determine the return level/period of the variable, should be a command in this package that shows 4 different plots and one of them is the return level/period plot.

Anyone could help me?

It is very important for me.