The items you found in Fort Stag (along with the guys that came down from Oleg's) were worth 5 BP Total = 5bp
You spent 1 BP clearing out the rocks from the fort and thatching it. However the fort will now count as a fully functioning Watch Tower in when Horcroft is established. Total = 4bp
The first group of settler wagons Wagons that came along with Charles included families, goods and workers worth another 15bp.
Total available funds (at present) 19 bp
And there will be more wagons arriving shortly.