It's been awhile but I have at last done some more bias joined binding. Not only that but I remembered to photograph each stage (I think). I guess you could call it a tutorial but so many have done it before and I don't even think it is different, anyway I ramble...
Leave about 6 inches free at each end and each end should over lap by the width of the binding and a bit more.
Lay the binding out and crease each end so they join (butt them together)
Cut one end to the crease
With the bit cut off open it out, lay it on top and perpendicular to the other side (this give you the join point plus the width of the binding)
Cut any excess off (cut is made on the further side from the crease)
Putting right sides together, lay the shorter end perpendicular and on top of the other side. Draw a line across the square that is made.
Stitch along that line.
Check that the stitching is correct in direction and length before trimming
If you stumble across these instructions, hope they help. Enjoy!