Joining a Private Debt shop from vanilla LevFin. Any resources for learning the basics of mezz/pref/subdebt?

I'm starting a new role at a credit shop that is focused on lending up and down the cap structure. My read is they do everything from unitranche down to mezz, pref, and equity coinvests. I'll be joining from a bank's LevFin team where I really only worked on more vanilla stuff like 1L term loans, bonds, and the occasional 2L term loan. I obviously know these instruments sit lower in the cap structure, but I don't know anything about their characteristics.

Can anyone provide any basic info on mezz/pref so I'm not totally behind? Key things I'm blind on are the following: How it's priced (Spread+OID like a 1L/2L?) Are most of these PIK? Typical size relative to EBITDA (turns of leverage)? Are these usually taken down by one party or syndicated? Are grids/term sheets somewhat similar to loan commitment papers/indentures or totally different? I assume covenants are similar to term loans but any nuances to be aware of?

Just trying to find the very basics so I'm not totally behind. Thanks!