Set the girder onto the structure's top plate. Adjust the girder so that it's sitting at the location where you'll attach it to the top plate and wall post.
Slip the top end of the anchor, which is U-shaped, under the girder until the inside edges are flush against the girder. Push the bottom tab so that it is flush against the top plate and wall post.
Hammer 16d spikes through each hole in the bottom tab of the girder anchor directly into the top plate and wall post.
Locate the holes in the side tabs that surround the sides of the girder. Hammer 16d spikes through each hole. Continue hammering nails through the anchor plate on the opposite side of the girder.