Parsing - Extract Characters From A Long String And Reformat The Output To CSV By Using Keywords With .net?

I have a task to resolve, it is regading extracting characters from a long string to the console, the extracted text shall be reformatted and saved into a CSV file. The string comes out of a database.

It looks something like: UNH+RAM6957+ORDERS:D:96A:UN:EGC103'BGM+38G::ZEW+REQEST6957+9'DTM+Z05:0:805'DTM+137:20100930154

The values are seperated by '.I can query the database and display the string on the console, but now I need to extract the Keyword 'ORDERS' for example, and lets say it's following 5 Characters. So the output should look like: ORDERS:D:96A then I need to extract the keyword 'BGM' and its following five characters so the output should look like: BGM+38G:After extracting all the keywords, the result should be comma seperated and look like:

ORDERS:D:96A,BGM+38G: it should be saved into a CSV file automatically.

I tried already:

'Lookup for containing KeyWords
Dim FoundPosition1 = p_EDI.Contains("ORDERS")
Console.WriteLine(FoundPosition1)

Which gives the starting position of the Keyword.I tried to trim the whole thing around the keyword "DTM". The EDI variable holds the entire string from the Database:

Dim FoundPosition2 = EDI
FoundPosition2 = Trim(Mid(EDI, InStr(EDI, "DTM")))
Console.WriteLine(FoundPosition2)