In serial, one effect's output feeds the next effect. Parallel splits the signal into two paths so effects can process different branches. A merge combines branches before shared effects or the output.
Start with a simple path
For electric guitar, one starting point is: gate if needed → compressor → boost or drive → amp → cabinet → EQ → modulation → delay → reverb. Change the order to suit the goal. Volume before Delay/Reverb preserves tails when you turn new notes down; Volume afterward turns the tails down too.
Add a branch
Use the board's path controls to add a split. Choose a branch before placing a pedal and check the destination indicator. Balance branch levels; adding two identical signals can raise level by about 6 dB. Paths with different phase, filtering, or delay can partially cancel. Listen in mono too.
The three-dot routing menu offers actions suited to the current path layout. When returning to serial, check the resulting effect order and the position of shared effects after the merge.
Stereo mix or Separate A/B
Stereo mix combines paths according to stereo routing. Separate A/B sends branches to separate output destinations and needs suitable physical channels. Two paths do not automatically have stereo width if both carry the same information.
A safe final meter does not prove every earlier stage is clean. Use each effect's IN/OUT to trace level changes. Test tails and preset changes on the rig you will use.
Read about gain staging and signal summing.