I bought a Trek XM700+ around 2016. I've loved it, but I want to do a little of my own maintenance on it. My chain started dropping and in the middle of freezing rain I basically had to break my chainguard to get the chain back on enough to ride home. In light of that, and since it's probably time, I'd like to replace the chainring, chain, and maybe the chainguard. The following are what I've ordered and what I need help with:

• I ordered KMC E-10 chain
• I'm waiting on the octalink crank puller to arrive
• I bought the Bosch lockring removal tool
• I don't know what chainring to get, neither the number of teeth nor the offset
• I ordered a Miranda E-Chainguard Nut. I'm not sure I'll get a whole chainguard like was there before or not, I'm hoping this will suffice at least to prevent the chain drops
• Lastly, for reference purposes, I'm trying to decide which generation this Bosch system is, I think it's a gen 2 Performance Line, is that right?