Laying pavers for a 15x15 patio in backyard
A few thoughts, I am no expert but have laid a few walkways before.
And you do need a good solid base for the pavers to sit on. I have used crusher fines before.
Like anything, preparation is the key to a good job. You want to remove any sod or vegetation. And then depending how high you want the pavers to sit, remove soil also.
What we have used in the past is metal edging from Home depot.
It is pretty rigid stuff, but you can flex and bend it around corners. Makes for nice meandering pathways as they wind through the yard, or can give your patio rounded corners and curves, or just use it to create square corners.
So now you need to think, do you want the finished hight at grass level?
I think it looks nicer, in years to come will be easier to mow the grass and just run the mower on to the patio to cut.
With the metal edging we use, it will hold the sand or crusher fines in place and can be above ground level.
Now you will have to use a weed whacker to trim the grass around it.
So it is a trade off.
Is less labor installing it above ground level, less soil to remove, and you do need at least 2" of proper sand or a base under it, this gives you an idea how much soil needs to be removed, plus the thickness of the paver to get it to grass level.
Hope this answers your questions, you do not need it at grass level and simply more work installing. I think it is worth it for the good looks and ease of maintenance.
Yes, you do need a solid base under it. I know that there is sand designed just for pavers and will be fine to use it.
What I call crusher fines is basically the smallest microscopic pieces of gravel. It is easy to spread and compact. We used it for a driveway along side of the house for a customer. Dumped it in 4" thick and they used the bucket of the bobcat to spread and compact it smooth. Took about an hour for them and was done.
6 years later, still looks like new, and I had a dump truck in that driveway 2 weeks ago delivering material.
Sand will be fine, crusher fines will make that patio last a lifetime with foot traffic.
If it was easy, we would not call it work!