Understanding sequential solution for the TAOCP 3 Million Men problem The problem and solution of interest is described here: What does &gt; mean in this TAOCP solution?

Can anyone explain following points in that solution:


How exactly we can build (x[i], x[i+2]) for 1 &lt;= i &lt;= N-2 ? 
What exactly means "merge G with it"? Provide exact algorithm for merging these two files.
How steps 1-4 are executed? Is it:  

if (condition 1) {
    ....
}
if (condition 2) {
    ....
}
if (condition 3) {
    ....
}
if (condition 4) {
    ....
}


or

if (condition 1) {
    ....
}
else if (condition 2) {
    ....
}
else if (condition 3) {
    ....
}
else if (condition 4) {
    ....
}


?
With a for loop that steps through the array and creates a new pair from the $i$th and $(i+2)$th elements, for each $i$.
The same as the merge step in merge sort.
There are no "otherwise"s in the statement in English, so there should be no else statements.