Hi @jreynolds
Pretty easy to do just like making mud pies as a kid but just a little harder to get neat edges.
The simplest and cheapest way is to by bags of (Sand and cement) premixed and mix with stones in this ratio. 1 bag Sand Cement. Fill the bag with pebbles and one same bag of stones mix in a wheel barrow is the best or cement mixer
Or mix 2 parts sand, 1 part cement. 2 parts pebbles should do the trick. A thin 20mm needs to be a little stronger as long as this is people traffic only.
If you are doing this where cars will travel on it I would prefer researching many cement coloured sealer options some are stone like in finish this maybe the easierst option for your path too just roller it on. Small pebbles may even be cast it over the dried painted cement and apply a clear top coat of sealer.
Please try it on practice cement section 600mm square out of sight as it isnt specifically what I have done before
Spread the cement on path min 20mm deep. You will need form work to make a neat edge if your path is not allready between a wall and something else. Note well do this on a cooler day as 20 mm cement will start to dry out in an hour. And keep pre wetting old pressure washed (or hosed or some times a air blower will do to remove loose dirt / rocks.
The best way to simple DIY form work do this is cut up strips of corfue (5mm thick) and attaching it to wood stakes push them into the ground or use old fence pailings for the edges for the cement. Corfu pretty flexable and great for curved paths but straight paths need peg every 60cm to stop corfu bulging out and not being straight.
What you want is the form work sitting in besides old path and sitting proud 20mm above the concrete path all the way down the path.
When you pour in the pebbles mixed in cement use a large hand steel float this will bring the pebbles down and the the cement slurry up move the cement left and right to simply fill the form work to the top . Do gently tap the edges of corfu as this will get the slurry form smoothly against the sides
Leave the cement partially set for 1 1/2 hours as a guide and gently hose the cement path with a wide spray untill pebbles just exposed use the water sparingly as you can hose out all the cement and pebble will be loose. Just add more cement and recover them no fowl.
Options
Use diff coloured sands white, red or yellow to color your path use oxide to color cement.
Add Glass stones. Or glow in the dark stones looks like a fairy land path no lights required.
Epoxy on cement with stones will work but not UV stable for more than 10 years.
There maybe pre mixed pebble crete products at Bunnings i missed .
But simplest is the Concrete sealer options but not cheap .
