For someone who doesn't know what they are doing, you've done a wonderful job. Your website is nice and bright and I almost felt disappointed when I reached the bottom.
A few things I would say:
Make some of your sections smaller else there is a lot of wasted space and a lot more scrolling for the user.
Personally I would add more images of spray tanned people in the sections without images, just to keep peoples attention.
The font in the paragraphs of each section is a little small.
On the Book Now page, there are too many buttons all pointing to the same page, which you've also included on the page.
If you are going to use that many buttons, then make the button go to the correct option, because at the moment it takes one to a page and then one needs to find the option in the list. Eliminate that step.
Also bear in mind when a button is clicked your website is gone from the users browser. It looks like the schedule page is not linked to your website theme. I am guessing this page is older and your website is the newer of the two.
One should never take focus away from your main website. You want to keep people on it for as long as possible. Therefore you need to fix it that when the button is clicked it opens a new tab.
Or at the very least the Schedule page should have the same look and feel as your website, with easy access to the menu bar.
Why not re-create this schedule page in your Squarespace website.
That is just a few things I noticed. I hope it helps.