NEED HEPLP: structuring application for a SEO company

NEED HEPLP: structuring application for a SEO company

I have tried doing this myself but am getting confused on how to structure an application for this project. If someone(s) experienced could help me, I'd appreciate it.

The application is for keeping track of hundreds of websites, their promotion campaigns, their rankings in the search engines, development and maintenance. The websites need to be able to be dealt with both individually and as bulk groups.

The websites have a front page, and then 20 or more sub-pages. Each page on a website has 3+ keywords that each have their own rankings to record and track over time.

We also need to keep track of promotion types, start date, stop dates, and cost. 

Other things we to keep track of includes software platform the website is built on, tasks that need to be done--editing, updating, backups, etc.

My biggest confusion is how to set up the application--how do I keep track of the website name and then all the subpages--each with 3 keywords each--in an effective and simple manner, while still retaining the ability to analyze each website individually or in groups based on various factors.

Thanks in advance for helping!