The "How to Transcribe Music" was very helpful but there is no "How to Arrange Music" Thread
I need some help
any ideas?

What notation software do you like to use? Finale, Sibelius, and Lilypond are a few examples, or you could do it by hand. If you can read sheet music then arranging it should be a breeze.

If you want to take an original score or song and arrange it for piano, then for starters just pick out the melody for the right hand or upper staff, and the harmony and bass in the lower staff or left hand. Since it's an arrangement, you may semi-compose it as well, particularly the harmony. You don't have to strictly transcribe it note for note.

Finale
Im trying to arrange solo pieces into string quartet

BTW brncao
thanks for ur help in the first thread

There's really no strict way on "how to arrange music" since there are many choices an arranger can make. What I would recomend is studying up on instruments. Memorize their ranges. Know their limitations. Know how they sound in different registers.

But if you're looking for something to read, I suggest reading through this: http://www.northernsounds.com/forum/forumdisplay.php/77-Principles-of-Orchestration-On-line