I will show you how I made a wide paracord bracelet with a side release buckle. This is also a good plan for a collar for you dog.
Step 1: Pick your colors
Also for your side release buckle I recommend a 1" size. This allows you plenty of room to insert the cordage. The 5/8" size I used just made it very tight to work with.
To figure out how much paracord you will need, measure your wrist where you want the bracelet to sit at. Take that measurement and multiply by 12 to get your approximate start length. You should have plenty of cord left over at the finish. It's better to have too much than not enough.
The color you want as the outside one should be your wrist measurement times 12. You should make 2 lengths of this. The color you have for the inside will be twice as long as the outside color or 24 times your wrist measurement.
Loop the strands onto your buckle using a cow hitch knot
One tip is to make sure you keep the same pattern going and not switch which cord goes over and which one goes under. If you do switch the order it will make the pattern look disjointed.