Make me an Rstudio code. With the following outline.

1) Brief description of the stocks/ETFs/ company Start - 1/1/2015 UNTIL 12/31/2022

2) Descriptive statistics

3) Portfolio Creation

a) equally weighted

b) minimum variance

c) maximum returns

d) with constraints (a certain level of weights)

e) with rebalancing

4) Conclusion

Additionally, add the codes for the variables that will be utilized.