There are several stages but the crossing over starts on the second stage. And the actual crossing sides happens on the following stage. Hope this helped :)
Remember meiosis is the process in which the cell will divide and at the end will be 4 new cells with the half of genes each one. So at the begging of the process ( in the interphase) the cell will start to collect all the compounds, nutrients, etc. to duplicate its genetic information. The next stage ( the prophase), the cell will duplicate and recombine their genetic information ( that means cross over). In the next stage ( the metaphase), the four tetrads (the four similar genes that were duplicate), they start to align in the spindle fibers to start the first cell separation.
Asexual reproduction is when you don't need another partner to reproduce like plants. Sexual reproduction is when you need another partner to reproduce like humans and animals.
