Setting Players Scales with triggers (Using 1.21s generic.scale)

Need help with triggers for this pack, I have not used them before
I have 3 functions that are called on tick
scale_normal
scale_small
scale_tall
These functions should set a players scale to the respective sizes, 1, 0.5, 1.5
Here is the code from scale_normal
# Set player size to normal (1.0)
execute as @a[scores={scale_normal=1..}] run attribute @s minecraft:generic.scale base set 1
scoreboard players set @a[scores={scale_normal=1..}] scale_normal 0

How can I add triggers
E.g. /trigger scale_normal that will then run these commands, I know I need to set the player who runs the commands score for the respective objective to 1 and the rest should already be handled, But what I can't figure out is how to add the triggers