Dreamweaver and MySQL database

You can find tutorials to accomplish every part of this, but what you are describing will require quite a bit more expertise to accomplish than just building your website. You will connect your website to MySQL using the PHP programming language. Most of what you will need to do will involve writing PHP code. There won't be a whole lot to do directly in MySQL.

If this is something you really really want to do yourself, or you have zero money to spend, then I guess you can try going down this road, but otherwise it makes more sense to hire someone to build it for you.

Why learn to rebuild your automobile engine if you only plan to do it once? Makes more sense to hire a mechanic who devotes his career to doing the work, has all the tools, etc. Likewise, some of us spend 40 or more hours per week, for years, building projects like the one you have described. I can promise you that if you try this, you may succeed. . . if along the way you don't go mad with frustration first. When I first started working with PHP it sometimes took me days to solve problems that take me a few minutes now.

When you put a database behind your website and make the site dynamic, you open yourself to hacker and spambot attacks which your site is not now vulnerable to. Security becomes a huge issue. Some of my websites come under attack every single day. The hackers and spambots WILL find your site and they WILL exploit anything they can, so you will need to be prepared.

Maybe a simple alternative to your plan would be to email every employee the PDF of their payslip. This process can also be automated, so you would not have to prepare and email each one yourself, but it would be a far smaller project.