Q) How to fetch & decode compressed instructions

[mbaykenar]

I wonder how compressed instructions are reside inside memory? I know their lengths are 16-bit instead of 32-bit.
A memory can be looked like this:

Each line is an instruction | x is 4-bit
xxxx
xxxxxxxx
xxxx
xxxx
xxxxxxxx
xxxxxxxx
xx

I tried to follow RTL code and understand it but if some of my questions below are answered then I understand it better:

Q1) How to know how many bits to be fetched from instruction memory? If it is a compressed instruction and cpu fetches 4 bytes, then what happened to the next cycle? Maybe the next instruction is 32-bit?

Q2) I saw that inside picorv32.v module the there is COMPRESSED_ISA parameter but couldn't follow what exactly happens if COMPRESSED_ISE is 1?
So after decoding the increment value is determined according to the result of the decode operation ?

Please you can also direct me to the lines inside the modules where these kind of fetch & decode of compressed instructions are handled