Hello Science-projectsW and welcome to the forum,
there are lots of tools inside FreeCAD that you can use to avoid double work.
The Draft module has clones which allow to duplicat, scale and "mirror" objects.
Draft has the Array to repeat objects linear and polar.
The use of assembly2 can becomes clearer if you inspect the youtube channel of cad1919. There are some good demonstrations
Assembly2 support offsets but there are other tools too, look at the lattice2 workbench. Part Compound is an other good friend.
Look at these first and then ask your specific questions again. We will support you.