Before plugging in any cable, look at the plug and matching socket. Make sure that they mate exactly. There should be no need to force anything. If a plug is fighting you when you try to insert it into the jack, stop. It may be upside down, or does not have the right number of pins.
Most damage occurs where people use too big a hammer.
Note that there are screws to fasten some plugs. While you can still see the back of the machine, record the Serial number in your manual. If there are audio components, locate the proper sockets for each. As long as you don't try brute force, or drop it on the floor, you won't damage your computer. When all the components are interconnected, and all the power switches are off, insert the plugs into an electric outlet.