Construct a diagram of your rig. Sketch a square for each amplifier, draw a circle to represent each input and a broken circle to represent each output socket.
Make a key for all of your components. There may not be sufficient room on your diagram to include the full name of each piece of equipment; use abbreviations and write down the full name next to each abbreviation on a separate sheet. For example: "DD = Digital Delay" or "SB = Splitter Box."
Plot your signal chain. This is the order and number of components, such as effects pedals, between your guitar and amplifier. Units in a signal chain have a large influence over the guitar tone, as they process the guitar signal before it is amplified. Denote signal-chain effects with a straight line between each unit. Draw a straight line from the final effect unit to the front of the amplifier symbol.
You can also put effects in an effects loop, using them to "send" and "return" jacks on your amp. This method lets you plug the guitar directly into the amp. The effects influence the guitar sound after amplification, resulting in a more subtle influence. It allows for a cleaner sound when the effects are bypassed. Denote effects-loop units with a curved line from the back of the amp to the first effect, straight lines between each unit and a second curved line from the final effect to the back of the amp. Modulation and delay pedals are typically more effective in a loop rather than in a signal chain.
Indicate any split signals with arrows. If you are using a splitter box to divert your guitar signal to two separate amps, draw a box to represent the splitter and mark with a clear "SB." Use an arrow indicating to which device the splitter box sends the signal.
Indicate the basic characteristics of your amplifier. Use "T" to indicate a tube amp and "SS" to indicate a solid state amp. Write the number and size, in inches, of the speakers in the following manner: for a pair of ten-inch speakers write 2x10. For two pairs of 12-inch speakers, write 4x12. Speaker configuration is relevant because it may dictate which splitter-box output you use.