Documentation second draft

[anitaapplegarth]

Issue

• Which issue does your pull request address? If none of the existing issues are applicable, you can write a new issue.

Testing, documentation, and checks

• If your pull request introduces new code, you should write automated tests (explained here).
• Check that all tests pass using devtools::check().
• Check compliance with the preferred R style using lintr::lint_package().
• Build documentation using devtools::document().
• If you changed the readme, run knitr::knit("README.Rmd").

Pull request

• Assign at least one reviewer.

[mghosh00]

Looks great!