" The parseInt() function parses a string and returns an integer. It takes a second argument for the radix, which specifies the base of the number in the string. The radix can be an integer between 2 and 36.

The function call looks like:

parseInt(string, radix);

And here’s an example:

var a = parseInt("11", 2);

The radix variable says that “11” is in the binary system, or base 2. This example converts the string “11” to an integer 3.

Use parseInt() in the convertToInteger function so it converts a binary number to an integer and returns it."
Could someone explain all this to me
All this is a BIT TOO complicated for a beginner like me

If you are working with numbers in the base ten system (the number system that humans use) then you don’t have to worry about the radix. If you are using parseInt to convert from another number system (binary, octal, hexadecimal, etc) then you need to worry about it.