Android Bot Maker

I am inexperienced with coding in general but i was using an Android application "Android Bot Maker" to make a macro. However, I do not know how to make it so that instead of inputting text that I assign it inputs a random string of an assigned number of letters.

The exported file is attached and : input text 'THIS%sIS%sWHERE%sI%sNEED%sRANDOM%sLETTERS'

is the place that i want it to input a string of 20 alphanumeric characters instead of THIS IS WHERE I NEED RANDOM LETTERS.

Is there a way to do this so that it will function on android?

 while true
do {
echo 'TAP: (600,1200)'
input tap 600 1200
echo 'SLEEP: (1.0secs)'
sleep 1.0
echo 'TAP: (100,300)'
input tap 100 300
echo 'SLEEP: (1.0secs)'
sleep 1.0
echo TEXT: (rawrxd)'
input text 'rawrxd'
echo 'SLEEP: (1.0secs)'
sleep 1.0
echo 'TAP: (150,360)'
input tap 150 360
echo 'SLEEP: (1.0secs)'
sleep 1.0
echo TEXT: (lolayy)'
input text 'lolayy'
echo 'SLEEP: (1.0secs)'
sleep 1.0
echo 'TAP: (150,605)'
input tap 150 605
echo 'SLEEP: (1.0secs)'
sleep 1.0
echo TEXT: (THIS IS WHERE I NEED RANDOM LETTERS)'
input text 'THIS%sIS%sWHERE%sI%sNEED%sRANDOM%sLETTERS'
echo 'SLEEP: (1.0secs)'
sleep 1.0
echo 'TAP: (150,660)'
input tap 150 660
echo 'SLEEP: (1.0secs)'
sleep 1.0
echo TEXT: (thisisapassword)'
input text 'thisisapassword'
echo 'SLEEP: (1.0secs)'
sleep 1.0
echo 'TAP: (150,740)'
input tap 150 740
echo 'SLEEP: (1.0secs)'
sleep 1.0
echo 'SWIPE: (450,570) (450,1270) 1s'
input swipe 450 570 450 1270 1000
echo 'SLEEP: (0.5secs)'
sleep 0.5
echo 'TAP: (300,750)'
input tap 300 750
echo 'SLEEP: (1.0secs)'
sleep 1.0
echo 'TAP: (100,810)'
input tap 100 810
echo 'SLEEP: (1.0secs)'
sleep 1.0
echo 'TAP: (400,900)'
input tap 400 900
echo 'SLEEP: (1.0secs)'
sleep 1.0
echo 'TAP: (350,1200)'
input tap 350 1200
echo 'SLEEP: (1.0secs)'
sleep 1.0
echo 'TAP: (200,1000)'
input tap 200 1000
echo 'SLEEP: (1.0secs)'
sleep 1.0
echo TEXT: (JN1239601)'
input text 'JN1239601'
echo 'SLEEP: (1.0secs)'
sleep 1.0
echo 'TAP: (450,1070)'
input tap 450 1070
echo 'SLEEP: (1.0secs)'
sleep 1.0
echo 'TAP: (40,80)'
input tap 40 80
echo 'SLEEP: (1.0secs)'
sleep 1.0
echo 'TAP: (150,650)'
input tap 150 650
echo 'SLEEP: (1.0secs)'
sleep 1.0
}
done