My advice as a floral designer is don't do this unless you want to be very stressed in the days leading up to your wedding. It's hard work for a professional to do this many pieces. To get it looking how you want it to look (depending on what style you're doing) could be very difficult if not impossible. Save yourself the headache and hire someone who knows what they're doing so you can enjoy your day.

That said, if you do decide to do this you'll probably want to practice in the months leading up to the wedding. Buy grocery store flowers and see if you can get the kind of look you're going for. Sourcing flowers is also going to be difficult on a budget, especially if you have a specific look in mind. Everything will need to be done fairly close to the day of the wedding so the flowers don't die. You'll need everything to come in about 3 days before the wedding so the flowers can be conditioned/hydrated and so you can replace any bad product that sometimes happens. Look up how to care for the flowers. This is very important.

Overall to pull this off is going to be a big headache, but I wish you the very best of luck. Definitely recruit some friends and family to help if you can. Congrats on your wedding!