How to use [else-if]

The reference page of else-if has its arguments, constraints and declaration.

[else-if] is the younger sibling of [if], and must be preceded by its older sibling, or other [else-if] nodes, and will only be evaluated if all of its previous conditional slots evaluates to false - At which point [else-if] is allowed to test its condition - And only if its condition evaluates to true, it evaluate its lambda object. Semantically [else-if] is similar to [if], in that it requires two arguments with the same structure as [if].

.dest
if
   .:bool:false
   .lambda
      set-value:x:@.dest
         .:yup!
else-if
   .:bool:true
   .lambda
      set-value:x:@.dest
         .:yup2.0!

[else-if] can also be given an expression directly the same way [if] can. See the example for [if] to understand how this works.