That serial number is a way for the manufacturer to know when and where it was made, maybe by whom. At any rate this was made in China if it's fairly new. You would have to email the company to get any knowledge on this. Good Luck!
Usually the nut on the rear brake caliper is a 10mm. Loosen the nut and the caliper should spring open. Pull on the cable housing where it touches the caliper and it should pull out of the cable clamp that you loosened to start the process. Pull the cable housing off of the cable. Look at the cable and see if it is rusty. If it is then replace it. There is a good chance that the cable housing is rusty inside of it as well, it's a good idea to replace it too. Go to your favorite bike supply store and get a replacement cable and housing that is longer than the one you removed. When you get back to working on the bike , remove the cable from the housing, if it has an end on both ends of the cable cut the one off that you don't need. Once you have the cable removed from the housing pick up the cable housing, compare it to the original housing and cut the new one the same length as the original. Thread it back into the holders on the bike as the old one was. Now install the cable onto the bicycle. Let the new cable protrude out of the housing, thread it into the cable clamp that you loosened in the beginning, squeeze the caliper together and pull on the cable. Now that you are holding the cable tight with one hand take the 10mm wrench and tighten the clamp. Project finished.
On the right hand side of the crank or oppisite side of the front sprocket should be a 1 1/8 lock nut remove lock nut an washer should be an ajustable race with two holes known as a spanner race tighten up the race reinstall washer an lock nut tourqe down lock nut rotate crank making sure bearings dont drag an done If you need further help, I’m available over the phone at https://www.6ya.com/expert/robert_c7b5aba9012a13b2
I don't think the shocks are adjustable. Manufacturers pre-size them and unless you want to replace them with a pair more of your liking, you're stuck with them.
Travis:
Put the rear derailleur into second gear and stop the bike before it shifts back down. Look carefully at the derailleur and you will see two small screws next to each other. These are stop screws. The stop screw for high gear may be out of adjustment, or the front derailleur is out of alignment putting sideways torsion on the chain forcing the chain to drop back into first gear.
There are two small screws which control the travel limits for derailer systems. Normally located top left of front mechanism when viewed from side. Adjust to allow travel within limits of gearing. Make sure that cable is not slack when in low gear position.
Any Shimano rear derailleur that is specific to the amount of cogs you have in the rear will work. Alivio is the entry into the nicer derailleurs. The more money you spend, the nicer they get: lighter, more machining, a more precise fit of parts.
Any bike shop should have those. You may have to split the bad one with a razor knife to get it off. You may want to use soapy water to make putting the new one on easier.
While the bike is in riding position loop the chain on the back sprocket. If this is a single speed bike then place as much of the chain as you can on the top of the front sprocket. Once it is partially threaded you can crank pedal around a half a turn and the chain will pop on the rest of the teeth.
