It's best if you take the express train leaving from platform 2
I think it might be better if you take from platform 2 the express train
It's best( 一番いい) if you take the express train ( 快速を乗ったら)leaving from platform 2( 2番ホームから出る)
I think it might be better( した方がいいと思う) if you take, from platform 2, the express train( 快速、 2番ホームの、 乗ったら)