Need someone to interpret music sheet

Hi,

need someone to interpret the “things” on this music sheet. I’ve just begin to learn music with my kid. I came across words & symbols like semibreve, dotted minim, minim, crotchet but still very unsure about the term and how are they going to appear in the music sheets.
Hope someone can base on the attached “Hot Cross Buns” to explain about the music basic.

Thanks in advance:)