Rearranging Schedule resources will depend on what build of MacPractice you're on. There's a method used prior to MacPractice Build 7.0, and a method used from 7.0 onwards.
We'll cover both methods below. Be advised that rearranging Resources on one MacPractice client computer will change the resource order for all MacPractice client computers.
Rearranging Resources on a build prior to 7.0
This method applies if you are on MacPractice 6.1, 5.0, or 4.4.
Navigate to the Schedule Ability, and then expand the Resources node in the sidebar.
With the node expanded, you will need to click the resource you wish to move. This will select the resource. Next, you will want to click and hold the mouse button down, and drag the cursor to the left. If successful, you'll see a slightly transparent print of the resource name move along with the cursor. Then, with the mouse button still pressed down, you'll drag it into the desired position. You can place a resource in between two other resources by watching for the line in between each resource move with your cursor, as you can see in the animated GIF below.
This process can be quite finicky and may take some tries to get it to work properly.
Rearranging Resources on build 7.0 and above
Rearranging resources in 7.0 and above is simpler. You'll still navigate to the Schedule Ability and select the Resources node. However, from there you'll select the "Resource Order" tab.
You NEED to have a Resource selected in the sidebar, but once any Resource is selected, you can then drag and drop the resources in the desired order in the Resource Order tab, as shown in the animated GIF below.