Unlike sensible languages, literals are encoded in base 36, and each digit is mapped to a move on a Rubik's Cube. Luckily, there is a converter on the online interpreter.
For strings, "hi" would first become it's ASCII codes, [104, 105], then in base 36, ["2w", "2x"], then each of those digits mapped to a move and enclosed in S and S', S R2 B2 R2 b S'.
For numbers, the number is just converted to base 36 then has the decimal place (if present) replaced with M2. For example 12.34 would become ["c", "y"], then each digit mapped to a move, joined with M2, and put inside M and M' resulting in M U M2 b' M'. Note that to make a negative number you need to either multiply it by -1 (M M') or subtract it from zero.
Lists are notated with E and E' (the equivelent of [ and ]) and E2 for seperating list items.
Functions pop a certain amount of items off the stack perform an operation, then push the result back onto the stack. You can also preceed a function with u2 to make the function not pop from the stack.
R - Add
R' - Subtract (or if one of the arguments is a string and the other is a number, str.slice(0, -num)
L - Multiply (or in the same scenario as above, str.repeat(num))
L' - Divide (or if one of the arguments is a string, the string reversed)
L2 - Exponent (or if one of the arguments is a string, str.toUpperCase())
R2 - Nth Root (or if one of the arguments is a string, str.toLowerCase())
U - Modulo
D - Equal
D' - Not equal
F - Less than
F' - Greater than
B - Less than or equal to
B' - Greater than or equal to
D2 - And
F2 - Or
B2 - Not
r - Item at index b in a
r' - Index of b in a
r2 - Push b to a
u - Join list a by b
u' - Split list a at b
l2 - a.slice(b, c)
b - Print
b' - Get all inputs wrapped in a list
b2 - Push a copy of the stack to the stack
d' - Set the stack to the top item on the stack
U' - Pop the stack
l' - Swap the top two items on the stack
d - Push each item of list to the stack, (similar to ... in JS)
f2 - Exit the program
l - Length of a
f - Floor the top item on the stack
d2 - Push a random float to the stack
U2 - Range from a to b with a step of c
f' - convert a to data type b ("list", number, int, float)
Conditionals are written as x <conditional code> x2 <optional conditional code> x'. If the top item on the stack in truthy, the first block of code will run, otherwise, the second block of code will run.
For loops are created by pushing something to iterate to the stack, then pushing the name of your loop variable (as a string) to the stack. You can then use the enclose the code you want to loop in y and y'. To get the value of the loop variable, push it's name to the stack, then use the y2 command. To break the loop, use S2.
To create a while loop, use z <condition> z2 <code> z', The code will run until the condition is false. Exiting the loop is the same as exiting a for loop - S2. To make the loop run forever, leave the condition empty (in which case the z2 is no longer required) or provide it with a value that will always be truthy.
If you actually just read all of that, I'm sorry.