There is a tumbler just for mixing the cement.It holds 1of mix & you roll or tumble it. I have one, just haven't used it yet...
Here's one project using a walkmaker: https://www.hometalk.com/43401834/diy-patio-with-walkmaker-mold
not asking for a project, asking HOW to use it.
All you need to do is Google. Tons of free info. You Tube has lots of videos too.
It is very simple. We purchased one at a home show 25 years ago or so, still have it and loan it out to friends. The one we have uses one bag of quikcrete mix. Easy to measure and mark off and know how many bags you will need.