...if I may offer a coupl'a:

There are some great tutorials/sticky threads on this site for technique, but it's really pretty simple.

You need to carefully bend the main stalk of the plant (do it over a few days if it's already 'stiff' and not bendy), so that it runs parallel with the ground. Once this is done, use one string/tie/whatever to "hold the bend in place", and one string/tie/whatever near the (now-sideways) top, holding it in place.

The top will then try to outgrow its bonds, but any side branches that are now sticking up will become new tops. Carefully keep adding strings to 'catch' the escaping original-top, and try to 'chase' or 'guide' it around the main stalk in a spiral pattern for best effect.

Main thing to remember is not to 'lassoo' the bits you're trying to tie down, but to bend them carefully into shape with your fingers, and then tie 'em into position. LIGHT stress, after all

My biggest plant so far with this technique had over 30 flowertops on it.