Once you have added all the products you want to your cart, you can "View your cart" to check out.
From any page on the Soto website, you can click the little Shopping Bag icon in the upper right-hand corner (it's circled in red in the image below) --
Alternatively, each time you add a new product to your "cart", a box will pop up on the right side of your screen. If you want to browse or buy more items, you can click the "X" at the top of the page. Otherwise, click the "Check Out" button at the bottom.
On the next screen, you will see additional options for "Express Checkout", which allows you to pay through ShopPay, PayPal, GooglePay, or MetaPay. If you don't have one of those or if you wish to check out via the regular way, you can scroll down and enter your shipping and billing and payment information. If you have a discount code or gift card, enter it on the right (circled in red below) and click "Apply".
You can either use a saved address or enter your name and address in the available boxes -- remember to enter your apartment or unit number, if applicable!
You can also choose to "Save my information for a faster checkout" for the next time.