luvAR,
Welcome. Please don't get frustrated. There is a bit of a learning curve with certain concepts of this game, but that's what makes it so fun.
It took me quite some time to learn to use force paddles and there are still many facets of the dark force that I do not know about. Read through the thread that explains the force and try to duplicate some of the simpler paddles to learn the concept. The first time it spins will be very satisfying. It turns out to be a very interesting part of the game.
Some of your questions can be answered by going through the instructional levels at the beginning of the AR built-in levels, like applying timers, tension and other building tips. (If you have already have done this, it probably wouldn't hurt to breeze through them again.)
Timers however, like Rob said, cannot be added to existing materials, unless it is done in edit mode (found on the opening AR screen). This is the mode where you can design your own levels.
Level 43 solution by Hudak_160
One aspect of the force is that when you overlap materials or endnodes of like materials, the stress created can cause the materials to explode. (If materials are crossed, but the end-nodes don't intersect the material, there is no "force" movement involved. This is called welding and is considered "light.") In this solution, Hudak adds metal bars that overlap existing bars to strategically destroy them. If you zoom in and watch closely in slow mode, you can see this. Sometimes the added materials are added on top of existing materials and are not seen easily.
Incidentally, Hudak is the "inventor" of one specific type of paddle, named after him.
Level 44 solution by zx_1974,
A metal bar is added to the roundish figure and the force causes it to break free and spin. If you delete the added bar (the node is out of place just right of center) you will see the figure does nothing. It's partial destruction and random luck that causes the floor to get broken. A rope is added to the tram to release it and another bar is added to stop it.
Both of these solutions would be considered "dark"
for the contests and would only get a winning trophy in the dark category, if the score is better than the best "light"
solution.