This means: If there are no problems, there is no reason for us not to finish before or on Friday at the latest. In English we use "should" to when we mean that we expect something to happen if there are no complications: (friend): "I should be able to call you tomorrow." [if I don't have a meeting, etc.] (mechanic): "This should be easy to fix" {...but I'll let you know after I look at it.] (manager): "We should finish by 5." [if we work continuously and there are no interruptions.] Usually in this usage, we stress the word "should."

Her şey iyi giderse, cumaya kadar bitirmemiz gerekir. eldeki iş, proje, sipariş vb.

A: If we make no mistakes, we can finish on Friday.

Eğer her şey iyi, hazır cuma

"If all goes well" means if there are no problems. So, If there are no problems, the task will be completed be next Friday.