Rolling in a new timing chain can be as straighforward as Thomas describes. Just don't drop the chain down into the abyss. That can give you a few moments of terror.
Best to set aside lots of time to check and then re-check your work. This is not an extremely complex job, but it is not simple either.
When replacing that lower guide, sometimes called the banana slide, remember to remove the half round cover from just above the crank. It looks like you should be able to pull the lower roll pin without removing that part, but you can't. Don' tknow if that kit includes new roll pins, but if not then get them before you start the job. You should replace them too. BTW, that small cover just protects the front seal. It does't hold oil or anything.
Nothing to be afraid of really. Just be careful. Once the chain is set turn the engine over through several cyles to check, then re-check the timing marks. If it is off that can be easily fixed at that time. Just loosen the tensioner and the chain can then be rolled link by link over the cam sprocket into the corrected position. Use some wire ties or clamps when doing this. Then check the timing once again. A few of us have found the timing can be off by a tooth and it does not seem to show up on the intitial check. So the smart move is to roll the engine over many times and check the marks. One tooth is about 14 degrees, so it will show up clearly enough if you look.
Good luck with your project.