I would like to take a long position on Bitfinex
I have setup a trading account with 2.5 : 1 Leverage and funded the account with some coins.
Does that mean wtv order type i choose, it will be leveraged?
As long as you are on the 'Trading' page and not the 'Exchange' page.
Look at your 'Tradeable Balance' to see how much you have to play with.
What is the "Route order" check box?
Routing the order will send it to the MtGox orderbook and bypass the bitfinex orderbook.
Must i chose a "Maximum time to held the position" ? can't i hold my long forever ( as long as i don't get liquidated)
No, you can only borrow for fixed periods, but you can end a period early, or renew your position before it expires.
Is their a support thread or newbie guide for Bitfinex?
No, but one is badly needed.