I am still wondering/confused on the yard and which tracks and where they should have cross overs.
John, there's nothing magical about crossovers in the yard. They're simply placed wherever you think they might be useful based on how you intend to operate.

In this example, there's an engine on the Lt Blue track waiting to use the turntable. There's another engine on the turntable coming out of the roundhouse. For whatever reason, it wants to leave the yard using the Lt Blue track, not the Red track. So, it can use the crossover to do just that.

In this example, a train pulled into the yard on the Yellow track. The engine needs to get out, so it dropped the cars before the crossover and can use the crossover to the Blue track to "escape". The same is true if the train had come in on the Blue track. The engine could then crossover to the Yellow track to escape.

In this example, the small Blue yard engine just finished assembling a consist of tanker cars on the Lt Blue track. It now wants to combine the 2 Brown cars on the Red track with the 4 Brown cars on the Green track. It can use the Blue/Red crossover to pick up the 2 cars on the Red track, then move through the Red/Green crossover to attach them to the 4 on the Green track.
Of course, if you don't intend to perform these types of yard operations, then you don't need any crossovers. The idea is to provide some interest moving cars around to build consists, rather than just watch trains run. Or you might have a friend who enjoys yard operations. Or if you have friends over for an actual operating session where one will build consists while others run trains to various points on the layout delivering full loads and picking up empties, etc. Due to the limited size of the yard, these may not be totally prototypical, but hopefully they give you ideas for why crossovers are included in yards.