Ragbaby is usually presented as using a 24-character alphabet which combines I/J and W/X. This is historically accurate, but why it was originally constructed in this manner, I do not know.
In actual usage, there is no reason that a 26 or 36-character alphabet cannot be used, and since it is convenient to have numerals available when the plaintext contains many numbers, I have chosen to illustrate this cipher using the 36-character alphabet.
Using a selected keyword, construct a mixed alphabet, incorporating the numerals immediately after the associated letter, even if this results in inserting the numeral into the keyword. In this example I have chosen the keyword PERSISTENT SAVAGE. As always, duplicate letters are dropped when constructing the alphabet:
Keeping word divisions, the letters of the plaintext are numbered sequentially beginning with the first character of each word. Ciphertext characters are obtained by taking the letter that is the indicated number of places to the right, wrapping to the beginning when the end of the alphabet is reached:
Decrypting, then is the reverse process. Once the keyword and length of the alphabet is known, it is a fairly simple matter to construct the alphabet. Once that has been accomplished, the ciphertext can be numbered in the same fashion as the plaintext was numbered to encrypt - then, selecting the letter the indicated number of places to the left, the plaintext can be easily found.
Word divisions are kept as losing them would make deciphering very difficult, even if the keyword and alphabet are known.
Hyphens are dropped from hyphenated words and the word treated as a single word.