I've found these two websites that I think explain how to calculate the aguinaldo (xmas bonus) as well as the required vacation pay & premium (often paid at the same time as the aguinaldo). If anyone has any problems (hola Jo Anna!) figuring it out, pls. feel free to email me (pablot@shaw.ca) with your details and I'll try to help - I've gone through this several times with other amigos in La Manz. over the years.

https://yucalandia.com/2023/11/21/2023-aguinaldo-vacation-pay-rules-for-mexico/

https://soniadiazmexico.com/employee-benefits/