Why am I getting a Syntax Error

It is a very blatant syntax error.

For simplicity and to shorten formulas (often very significantly), I recommend turning off the Numbers preference "Use header names as labels". Your cell "Demand Backwood...." will get its normal cell name of B2.

I am assuming you want (in English) for it to be "if B2=low then 1, else if B2=medium then 2, else if B2=high then 2 (or should that be 3?), else 'empty' ". You can do this with nested IF statements or with IFS.

=IF(B2="low",1, IF(B2="medium",2, IF(B2="high", 2,"")))

That can be simplified if those are the only possibilities for what will be in B2 but I'll leave it as as it is for now.

With IFS it will be

=IFS(B2="low",1,B2="medium",2,B2="high",2,TRUE,"")

If B2 can only be low medium or high, you can shorten this formula some.

I'm guessing you're on an iPad. If so, you don't have the option.

On a Mac you would go to Numbers > Settings ... and under the General tab uncheck the 'User header names as labels' checkbox.

SG

For situations like this I find the SWITCH function the easiest to use:

Assuming the low/medium/high value is in B2, then:

=SWITCH(B2,"low",1,"medium",2,"high",3)

And fill that down the column.

If you want high also to correspond to 2 then simply change to this:

=SWITCH(B2,"low",1,"medium",2,"high",2)

More on SWITCH here:

SWITCH - Apple Support

SG