I'm creating a Schedule app. within a grid. Should I use a Border or Rectangle to make the Schedule?

Currently, I'm using a Border with 'tick marks' on the 15, 30, 45 mins of each hour of the day. The problem I'm having is placing the border at a specific location within the grid. Can someone tell me what the syntax of the HorizontalAlignment parameter is. I can't get the syntax correct.

Also, would a rectangle be better? It seems to have the same problem with HorizontalAlignment in that I can't get the syntax correct to place it at a particular location within the grid.

Sutton