2001 TRX 250ex

I had to buy new plastic and a battery for my quad.
As soon as I connect both the positive and negative wires to the battery, the quad begins to turn over to start.
No wiring came with the rear plastic I purchased. I believe I’m missing the wiring for the 15a fuse. What’s that wiring called, and could that be the reason to why the bike by-passes the push-button starter?

Any advice is welcomed.