Metacello is nice in this it gives very explicit information about dependancies, and it works in many Smalltalk dialects (and is actively maintained).  That said, it seems to be predominently driven and used in Pharo, so documentation will likely have some bent towards that platform.  Here is a reasonable introduction:

It is also worth noting that using Metacello will install that package into your Squeak - it isn't there natively.  The easiest way to load it into Squeak (that I've found) is to load a package managed by Metacello - it bootstraps itself in before loading the package you want.

All that said, I don't use it when I can avoid it. I do like looking at the dependencies, and then independently load them.  Obviously not all of us feel that way.

The other option as Monticello Configurations, which is part of Squeak already (and what underpins our Trunk mechanism, so it is guaranteed to be working).

To use Monticello Configurations, open "Monticello Configurations" (which is right next to Monticello Browser in the open (or apps or tools) menu).

Then, use the Add button to add the packages that you need to have loaded to support ClockAndCalendarMorphs (in the order they should be loaded).  Make sure to add the package  ClockAndCalendarMorphs las as well.

-cbc