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.
