diff --git a/01_set_extent.R b/01_set_extent.R
index f2dac1c..f5b0aaa 100644
--- a/01_set_extent.R
+++ b/01_set_extent.R
@@ -2,7 +2,7 @@
 library(nhdplusTools)
 library(sf)
 
-# set data dir
+# set hydrologic data dir
 data_dir <- "data"
 ifelse(
   !dir.exists(file.path(getwd(), paste0(data_dir, "/hydrologic"))),
@@ -15,6 +15,7 @@ nhdplusTools_data_dir(dir = paste0(data_dir, "/hydrologic"))
 extent <- read.csv(file = "extent.csv")
 crs <- 4269
 
+# make extent a polygon
 extent_poly <- st_polygon(
   x = list(
     cbind(
@@ -24,7 +25,10 @@ extent_poly <- st_polygon(
 )
 
 extent_poly <- st_sfc(extent_poly, crs=4326)
+# make extent a bounding box
 extent_bbox <- st_bbox(st_transform(x = extent_poly, crs))
+
+# make list of extent coordinates
 extent <- list(longitude_max = max(extent$longitude),
                longitude_min = min(extent$longitude),
                latitude_max = max(extent$latitude),
diff --git a/02_download_data.R b/02_download_data.R
index 0eeb0e0..c714b17 100644
--- a/02_download_data.R
+++ b/02_download_data.R
@@ -1,6 +1,5 @@
 # load libraries
 library(nhdplusTools)
-library(sf)
 
 # get watershed areas
 extent_huc <- get_huc(AOI = extent_poly, buffer = 0, type = "huc04")
@@ -12,11 +11,13 @@ download_nhdplushr(nhdplusTools_data_dir(), extent_huc$huc4, download_files = TR
 get_vaa()
 
 # combine data into geopackage
+# identify which layers to use
 layers <- c("NHDArea",
             "NHDFlowline",
             "NHDWaterbody",
             "NHDPlusLandSea")
 
+# save data into "data.gpkg" file
 data <- get_nhdplushr(hr_dir = nhdplusTools_data_dir(), 
                       out_gpkg = paste0(nhdplusTools_data_dir(),"/data.gpkg"),
                       layers = layers,
diff --git a/04_make_figures.R b/04_make_figures.R
index f6e03b5..ce1b1ec 100644
--- a/04_make_figures.R
+++ b/04_make_figures.R
@@ -17,7 +17,7 @@ units <- "in"
 res <- 600
 margin <- 0
 
-# set state to highlight
+# set state to highlight from political map
 state <- c("Wisconsin")
 
 # plot map
@@ -53,7 +53,8 @@ plot_map <- function () {
        add = TRUE)
 }
 
-# save figure
+## save figures
+## generate tiff
 # tiff(filename = paste0(figure_dir,"/map.tiff"),
 #    width = width,
 #    height = height,
@@ -65,6 +66,7 @@ plot_map <- function () {
 # plot_map()
 # dev.off()
 # 
+## generate jpeg
 # jpeg(filename = paste0(figure_dir,"/map.jpg"),
 #    width = width,
 #    height = height,
@@ -76,6 +78,7 @@ plot_map <- function () {
 # plot_map()
 # dev.off()
 
+# generate png
 png(filename = paste0(figure_dir, "/map.png"),
     width = width,
     height = height,