diff --git a/README.md b/README.md
index b80fde6..8a0bcfc 100644
--- a/README.md
+++ b/README.md
@@ -1,5 +1,26 @@
 # gunzip_fqgz_process
 
-The nextflow wrapper for the `gunzip` process.
+## This nextflow wrapper helps to implement `gunzip` process of a `fastq` pipeline that includes:
 
-https://github.com/nextflow-hub/trimmed_gunzip_fqgz
\ No newline at end of file
+1. Define a default parameter `params.trimmed=true`
+2. Check if the `inputRawFilePattern` is trimmed or untrimmed
+3. The `trimmed` file has `p` in the file pattern whereas untrimmed file does not have `p` in the file pattern
+4. Based on the file pattern the input parameter of the script is defined
+5. Execute the script to gunzip the input file using `gzip –dc` command and stores the output into the `publishDir`
+
+
+## Execute the script by using the following command:
+
+```nextflow run main.nf```
+
+You will see the execution of a `gzip` process.
+
+## Execute it again adding the -resume option as shown below:
+
+```nextflow run main.nf -resume```
+
+The -resume option skips the execution of any step that has been processed in a previous execution.
+
+## Adding a publishDir directive to the gzip process to store the process results into a directory of your choice.
+
+In this script, it stores the result files locally into `results/gzip` directory.
\ No newline at end of file
diff --git a/main.nf b/main.nf
index 4c543d4..0e5e0a3 100644
--- a/main.nf
+++ b/main.nf
@@ -1,13 +1,22 @@
 #!/usr/bin/env nextflow
 
-
+/*
+#######################
+Code documentation
+#######################
+1. Define a default parameter `params.trimmed=true`
+2. Check if the `inputRawFilePattern` is trimmed or untrimmed
+3. The `trimmed` file has `p` in the file pattern whereas untrimmed file does not have `p` in the file pattern
+4. Based on the file pattern the input parameter of the script is defined
+5. Execute the script to gunzip the input file using `gzip –dc` command and stores the output into the `publishDir`
+*/
 
 /*
 ################
 params
 ################
 */
-//NOTE: default parameter
+
 params.trimmed=true
 
 
@@ -20,7 +29,7 @@ NEXTFLOW Global Config
 
 inputUntrimmedRawFilePattern = "./*_{R1,R2}.fastq.gz"
 
-//NOTE: This pipeline is starts with `trimmed` because of the `p` in the file pattern.
+
 inputTrimmedRawFilePattern = "./*_{R1,R2}.p.fastq.gz"
 
 inputRawFilePattern = params.trimmed ? inputTrimmedRawFilePattern : inputUntrimmedRawFilePattern