The simplest form of how to split the string into words considers any whitespace as a separator. In detail, the whitespace is defined by the IsSpace function in the unicode package:
'\t', '\n', '\v', '\f', '\r', ' ', U+0085 (NEL), U+00A0 (NBSP).
The Fields function of the strings package could be used to split the sentence by the whitespace chars as mentioned earlier. The steps 1 – 5 cover this first simple case.
If any other separator is needed, the Split function comes into play. Splitting by another separator is covered in steps 6 – 8. Just note that the whitespace in the string is omitted.
If you need a more complex function to decide whether to split the string at a given point, FieldsFunc could work for you. One of ...