Newbie needs advice

[Trakyan]

I've never owned a 3D printer before. Heck, I've never even USED one ... but I sure as heck WANT one. I've been watching YouTube videos, trying to learn as much as I can prior to purchase. Can anyone tell me anything about Simpify3D software?

There's a couple of free programs I have, but it seems like it's taking an ENORMOUS amount of work to do even simple things. Let me tell you some of what I want to do:

1: I want to be able to manipulate objects in 3D. That is, if I have a gear, connected to another gear, is there a program that will show me what happens if I rotate them?
a. I have a gear. I have a long bar. I've joined the two together. I'd like to have another gear interface with the first, so I can push a lever that rotates the 1st gear, which then, in turn
rotates the 2nd, which (because it's attached to the bar) rotates the bar.
2: I want to take a 3D design (such as the U.S.S. Enterprise), and cut off certain parts - leaving me, say, with just the saucer. Then, I want to be able to create new parts to be "added" on top of the saucer (equal creations, left to right). I also want to be able to combine parts from OTHER 3D models.
3: I'd like to be able to take a 3D model of a figure - say, a Warrior with a sword - and make slight modifications to it - delete a beard or add one; change the size or shape of the sword; change the armor (if I have other armor to meld in over the 1st set).
4: I know Simplify3D will show me a preview of the print, slice by slice, and allow me to change the infill. Can it do any of the other things I've mentioned?

I'm not sure I'm explaining myself well, but I sure could use some pointers.

You have some misconceptions about Simplify 3D, what it is and what it does. It is a slicer that converts your 3D model into instructions for your printer, that's about it. It can move and arrange objects on your print bed for a job but that's as far as it goes. It does not make models.

1) That is not the job of a slicer (what S3D is), it's the job of a constraint solver, a lot of 3D modeling programs have this. FreeCAD, fusion 360, solvespace and more. What exactly is taking a long time here? It's a fairly short and sweet task in any modeler that can do it.
1) a) again, the job of a constraint solver. Nothing to do with a slicer.
2)If you just want to combine pre existing models, meshmixer is probably the simplest software. If you want to make models like props or characters from movies and games, a parametric modeler like fusion 360 or freeCAD won't work as well since they're suited for engineering shapes, not organic ones. The issue here is that organic modelers that you'll want for these types of objects don't usually have constraint solvers (for your gears and such), I think blender does. Another thing is organic modelers aren't suited to making engineering parts like mechanisms and gears and stuff. You'd probably need to learn two programs for your two separate needs.
3)Things are not nearly as simple as what you're describing ('delete the beard') unless someone made the beard as a separate part, and when using an organic modeler people rarely (never?) do this on purpose if at all. The beard is part of the head, and you'd need to remove it yourself, and then sculpt the details in to replace the beard. Think of it like a clay figure, you cant just 'delete' a beard on a clay figure, you need to cut it off then re sculpt what is underneath. Same goes for everything else you're asking about in #3.
4)No, it can't.

Your complaint seems to be that the software you have is taking 'a lot' of work to do 'simple' things. The thing is, you'll get better and faster at doing things with practice, and the things you're expecting to do are not simple. For #1 it's fairly simple in a powerful CAD program. For #2 cutting and combining models is relatively simple, but creating a part of the design yourself is not. For #3 these things just aren't simple, everything here requires you to sculpt the model yourself, at which point there isn't much point in using someone else's model.