So I want to start using Electrum. Do I use it to access my Armory wallet or do I have to create a new wallet with Electrum and make a transaction from Armory to it?
even if you choose any other wallet it is always wiser to create a new wallet and then make a transaction to send your funds from the old wallet to the new one instead of importing the old one into the new one like importing your private keys.
Also, if I (for some reason) lost my wallet but know the password, could I retrieve it or would it be gone? I noticed the app creates a file that stores the wallet locally. So, if that file is gone forever does it mean my satoshis are gone forever too, or is there a way to get my satoshis back in case that file went missing?
Electrum is a Hierarchical Deterministic (HD) wallet which means it is using a master private key to generate all the keys in your wallet. this master key is shown to you in the form of a bunch of words known as "Seed". all you need to do for back up is to write down this Seed somewhere and keep it safe. later on if you wanted to recover your funds then you simply start Electrum and instead of creating a new wallet and generating a new Seed you give it your old Seed to recover from.