Hi Richard,
next time you reply to a topic, after clicking on 'Reply', have a look at the previos posts (below the text box).
On the right of each posting, you will see a link 'insert quote'
Click on the link, and the post will be inserted in the text box, enclosed in quote tags ([ quote] .... text ... [ /quote]
Delete any thing you (within the tags you don't want, take the cursor to the end of the line (after the final /quote] (that's the bit Andrea forgot

) and press enter.
add your text, and there you are (use preview to check it out)
Another way is to click on the BCC quote icon (BCC tags, second line, second in from the right) and then scroll down, mark a text from another post, press <ctrl> and C (copy to clipboard), scroll back to the text box, and with the cursur between the ] and [ of the quote tags, press <ctrl> and V (insert)
Try a reply on this post to practice, and use the 'preview' to check.
Good luck
Bob