Update file_combinations.md

docs/howtos/file_combinations.md

@@ -1,7 +1,24 @@
 Sometimes you need to create all the possible combinations of a set of files
-that you have as file streams. This you can do with the
-[FileCombinator](https://godoc.org/github.com/scipipe/scipipe/components#FileCombinator)
-component.
+that you have as file streams. 
+
+For example, say that you have two file streams:
+
+```
+[a.txt b.txt]
+[1.txt 2.txt 3.txt]
+```
+
+... and you want to process all of the combinations of these two sets of files.
+So in other words, what you want is:
+
+```
+[a.txt a.txt a.txt b.txt b.txt b.txt]
+[1.txt 2.txt 3.txt 1.txt 2.txt 3.txt]
+```
+
+This is something you can accomplish with the [FileCombinator](https://godoc.org/github.com/scipipe/scipipe/components#FileCombinator)
+component, available in [SciPipe 0.9.1](https://github.com/scipipe/scipipe/releases/tag/v0.9.1)
+and later.
 
 ## Example
 
@@ -15,7 +32,7 @@ numberfile_2.txt
 numberfile_3.txt
 ```
 
-... and you want to create all combinations of the letter files and the number
+... and you want to create all combinations of the `letter*` files and the `number*`
 files, you can do it as follows:
 
 
@@ -46,15 +63,26 @@ func main() {
 }
 ```
 
-This will generate the following files (excluding the accompanying .audit.json files):
+Note that when accessing an in-port on the FileCombinator with the `In(PORTNAME)` method, this port
+will be created automatically, together with a corresponding out-port which can be accessed with the
+same name, `Out(PORTNAME)`, as can be seen when we connect the fileCombinator to the catenator process
+further down in the code.
+
+The program above, if put in a `.go` file and run with `go run file.go`, will generate the following
+files (excluding the accompanying .audit.json files):
 
 ```
+letterfile_b.txt
 letterfile_a.txt
-letterfile_a.numberfile_1.combined.txt
+numberfile_3.txt
+numberfile_2.txt
+numberfile_1.txt
 letterfile_a.numberfile_2.combined.txt
+letterfile_a.numberfile_1.combined.txt
 letterfile_a.numberfile_3.combined.txt
-letterfile_b.txt
-letterfile_b.numberfile_1.combined.txt
 letterfile_b.numberfile_2.combined.txt
+letterfile_b.numberfile_1.combined.txt
 letterfile_b.numberfile_3.combined.txt
 ```
+
+As you can see, all the combinations of the