At which stage of life the oogenesis process is initiated?

Germ cells in mammalian gonads are produced by

How many spermatozoa are formed from one secondary spermatocyte ?

$A$ : In spermatogenesis, the first haploid forms are spermatids.
$R$ : All the end of meiosis cells have haploid set of chromosomes.

What is gametogenesis ? Explain.

What is the correct sequence of sperm formation?