Belts aren't fun to change on these cars. But then again it COULD be worse. The older model Sentra's you have to remove a wheel AND a motor mount to change out the common belts(Not even refering to the timing belt just regular belts). Look at your tensioner pulley is it on a spring loaded arm? If so then there is likely a square hole which a 1/2" drive ratchet will fit in. Get the belt in place and then put the ratchet on to pull that pulley out of the way and slide the belt in under it. Seriously I'd have t actually look at the engine to see what you'd have to do.