Here's how it works.
You go online and create an account. If you have a points card, you can link it to your account. This means you get the points for the groceries and makes it easy to find things you buy often. In fact, the site will tell you what you sometimes buy, as well as what you usually buy.
Pick a store, and start adding groceries to your cart. For things like apples, you choose how many you want, and the site gives you an approximate price.
When you've added everything, pick a pickup window. Windows are two hours long, and each one is assigned a cost (usually $3-$5). I picked the window that corresponded to the end of physio. You will be asked whether you'll accept substitutions if they're out of something, whether you're bringing your own bags, and any other notes for the person picking out your groceries.
During the two hour window, you drive to the store and park in one of the four marked spots, then call them to let the,minor you're there. They'll come out and get your bags, then pack up the groceries, wheel the out on a cart, and load them into the car. It usually takes about 10 minutes.
The only charge is the $3-$5 - and frankly, I impulsively buy more than that if I go in.
Since that first time, it has become the way I shop. I don't have to wander the aisles looking for something I buy once a year, I can check to see what we have, and I can add items to my cart as I think of them.
The only downside is that you can't make changes online the day of pickup, even if you placed the order that day. But till live with that.