Walk ---- the bridge,---- the---- ----- ----- the left and t

Walk 【across】 the bridge,【take】 the 【first crossing/turning on】 the left and then 【go straight on】 until you reach the end.
go straight on 表示“一直向前走”,介词on可以省略,比如：
Turn right at the next corner and go straight on.
在下一个拐角处向右转,然后直行.
Go straight on and turn left,then you can see it.
一直走然后向左转,然后你能看到它.
更上一层楼!(⊙o⊙)

Walk (across) the bridge,(take) the (first) (turning) (on) the left and then (go) (straight) (on) until you reach the end.
穿过桥，在第一个楼口左拐，然后一直走到路的尽头。