How to make a homemade birdbath?

Hello, i have good news, some birds liked to bath and drink water from it.
That was very emotional¡
Here are the photos:

First some Saffron finchs showed some interest at the birdbath.

After some minutes more, one decided to take a look to the bath and looks like she tooks a bath¡



After that, other birds came but they weren’t interested and left.



But Saffron finchs have much interest and Eared doves are starting to like it to¡




I’ve read that cement can intoxicate birds cuz it makes water alkaline because it’s not fully cured yet, and that this alkalinity can be reduced or neutralized with vinegar, but i don’t really know how to verify this information, i’ll just keep that birdbath clean.