Ok I had the same problem for a while too understanding how arrows worked but it’s actually a rather simple pattern just different from how we’re used to thinking about operations.
Basically the number of arrows tell you the amount of times you repeat the operations that come before it.
Imagine for a second instead of using arrows the (+) sign in addition behaved in the same way the arrows did.
no problems but
If addition behaved exactly like the arrows then
Long story short the arrow just tells you to take the process used for the previous number of arrows and use a repeated form of that.