Associating task start date with project end date

Hi Everyone,

I'm fairly new to Wrike, so hopefully my question won't come across too simplistic. I have a large project I'm managing where all the task start dates are tied to project completion date. These are all new site openings, which means that we have a hard "opening" date and need to work backwards from there with all of the tasks that need to be completed to ensure that they're completed in time for the opening. For example, if a site is set to open on Nov. 1, a specific task would say that it needs to be started 30 days before site opening and will take 7 days to complete. This means that the task needs to start Oct. 2 and should be done by Oct. 9. How can I set up the individual tasks to follow this structure? Thanks for the help!

- Beth