Sounds like the switches for the pop bumpers and those rollover switches likely need to be cleaned and adjusted. Since those types of switches have gold plated contacts, it's recommended to use only a business card or a clean piece of paper slid between the contacts a couple times to clean the switch. A bit of isopropyl alcohol (I'll often use a qtip for it--use sparingly) is also safe for cleaning them. Don't file those contacts! (Note--certain switches have high-current tungsten contacts that are perfectly ok to file, you just want to make sure before you do anything)
You'll want to get a good switch adjustment tool, it's indispensable--especially compared with using pliers. Here's what i recommend, this way you'll be able to adjust switches from all sorts of angles, which you will likely find helpful: https://www.marcospecialties.com/pinball-parts/77-SWK
There's tons of info for your game here and elsewhere. One really good resource to start getting familiar with is pinwiki. This link will take you to the pinwiki section for your game (this Bally game uses a 6803 CPU chip, and so is often known as a "6803 game") http://pinwiki.com/wiki/index.php?title=Bally_6803
If you don't have the manual and schematics you can find links to download them at the internet pinball database aka ipdb.org. Here's the entry for your game, you'll find the operators manual/schematics downloadable links if you scroll down a bit.
Sooner or later you'll want to pick up a multimeter, doesn't have to be anything too fancy. Even a harbor freight meter can suffice, but if you invest in good tools, you'll save yourself a lot of unnecessary work and trouble (usually )...and you'll eventually want to get a decent soldering station, especially if you plan on doing your own circuit board repairs. If you don't plan on getting down to that level just yet, a basic pencil-type 25-30 watt soldering iron should be fine for wiring coils/lamps/switches/etc. Always use caution when soldering, and always make sure the game is off when working under the playfield (unless you're testing stuff, and even then with extreme caution).
It's an amazing community we have here, some really helpful and awesome people. Welcome to the addiction, erm *hobby* Good luck with your game, and if you ever get stuck and can't seem to figure something out or you have a question i may be able to help you with, feel free to pm me and I'll see what i can do.