Please don't post more than 2x in a row. Use the quote function instead and answer multiple posts in one or two posts. Thanks.
I'm not familiar with that function, would you mind just going through it with me?
Next to the quote button is a button that says "multi quote". Click that button on each post (save from the last one) you wish to quote (if you click them in order, it's much easier!). Once you've clicked on all of them, except that last post you wish to quote, click the normal quote button on the final post and it will take you to the reply screen.
At the reply screen you can split up quotes and answer them how you wish. It's as simple as using the return (enter) key and inputting text as you would anyway.
If you wish to read up on this further (or my explanation may be a bit too confusing!), check out the FAQ at this link