if you are familiar with bitcoin script, you might know there are a few important rules to following. first off, script is always found in a single operation. this is the reason we can at once break down script using the method of grouping each instruction together. if you want to keep things organized, you can keep your scripts in a single operation, one after the other. this keeps things a bit cleaner and makes it easier to understand, as you are not seeing separate instructions, but a single script.
let start out by examining an older bitcoin script. 1 op_checkmultisig. an important instruction we want to examine is the 1 op_checkmultisig. to start out with, we need to know that this is a one-operation script. so, to start, we need a place that we can start our script. as stated before, script is always found in a single operation. this is why we should always look for a single script, as a single script is one operation. in this case, we could either start from a script with 2 op_checkmultisig or from a script with one op_checkmultisig. lets look at the first script, with the two op_checkmultisig in it: op_1 op_2 op_3 op_4 op_5 op_6 op_7 op_8 op_9 op_checkmultisig. if you have followed the steps to break down script, you should see that we have a script with 2 op_checkmultisig. from here, we can look at the next instruction in our script, which is an op_equal. this is our first operation, and from there, we look at the second operation. this time we have an op_1 op_2 op_3 op_4 op_5 op_6 op_7 op_8 op_9 op_10 op_11 op_12 op_checkmultisig. now, we can continue to examine our script in this manner. the next script in our script would have to have the following: op_1 op_2 op_3 op_4 op_5 op_6 op_7 op_8 op_9 op_10 op_11 op_12 op_13 op_14 op_15 op_16 op_17 op_18 op_19 op_20 op_21 op_22 op_checkmultisig. as you can see, if you break down script in this manner, you can continue to break down script, until the last one in the script. this is how you should break down script as well.