Welcome to the forum Angela0912! Sorry to hear about your frustrations; however, I can assure you, there is nothing to feel overwhelmed by in this hobby.
Personally, I feel that many of the gadgets and gizmo's that hobbyists can find from time to time are simply gimmicks that we can do well with or without their help...in fact, in some cases I would say that they can be completely useless. That being said, I might lump the whole battery operated gravel vacuums in the 'with or without' category since there are other, much cheaper and much easier to use methods of gaining the same benefits.
Arguably the more popular and more effective gravel vac is the "python". While I believe that the term 'python' is more of a brand name than anything else, this sort of gravel vacuum is based on the relatively simply concept of a siphon. What's better is that they can not only be found in almost any LFS I have ever been in/heard of, they can also have a 'power assisted' option in which we can simply hook them to a sink in order to start and keep the siphon action working, but also to help keep the siphon action strong enough to 'suck up' detritus, removing it from the tank. In fact, I really enjoy the fact that, when using a sink/faucet, the detritus is simply goes down the drain so there is no need to deal with a bunch of gross and nasty water.
To help you get a better idea of what I am talking about in a visual sense, as well as to help support my comments here, check out this thread in the forum's DIY section by clicking
HERE. This thread, created by another FTF moderator and great asset to myself and our members, GM333, details not only how a python works, but also how to make your own (which I can vouch for the fact that money can be saved by going with the DIY option). This should get you headed in the right direction by at least answering some questions and perhaps, helping you to formulate more specific questions in which we would all love to help you with.
Again, I promise you that there is nothing to be overwhelmed by and if you ever feel frustrated or confused about anything aquatic, please feel free to pick our brains! Since joining this forum almost a year ago, I have found that there is no question too large (or too small) or too complicated for at least one member here to provide an answer, info, idea, or suggestion about. As always, welcome to the forum and I look forward to talking with you again soon!
P.S. Feel free to use the links in my signature below to learn more about FTF's useful features, including the abundance of basic information in our article section and how to pose any questions you might have in order to get the most rapid and accurate replies!