Part of the difficulty may be because you're looking at the result of existing projects. That can be overwhelming or at least time consuming to digest.
If you're interested in audio, your first project can be making a very basic audio amplifier with a single op-amp and some supporting passives, one of which is a potentiometer to adjust the gain. Connect an old radio, MP3 player, etc. into the circuit and play the result on a speaker. You can hook up your oscilloscope as well to see what you're hearing.
Play around with it and see what happens when you change the value of the various components, overdrive the input, use too much gain, etc. Also try different op-amps.
Once you fully understand that, make a couple more and figure out how to combine their output to make a mixer.
Then, make some filters: low-pass, high-pass, band-pass. Combine several of them to make an equalizer. Add that to the mixer.
Depending on how your original amplifier was built, you might now require a mic pre-amp. Make that and add it to the mixer so you can have mic- and line-level inputs.
See the pattern? Start with very basic components that you can play with, understand, and break in isolation. When you're comfortable with each one, add it to the larger project.
Imagine if you just looked at the schematics for a full-blown multi-channel mixer with preamps, parametric EQ, etc. It'd be overwhelming. Instead, build it in pieces that you can digest. When you're all done, make the final schematic of it and overwhelm your friends.
Edit: Don't forget to build a nice little linear power supply for your mixer.