That's it the egg tube. LOL Now if she's with eggs it's time to add her to the males tank and after a day or two you'll hae breed your betta's 24 to 36hrs later you'll have babys learning to swim. Now are you ready with food for the fry? After 4 to 5 days once there swimming like a normal fish and the egg shack is gone. They'll be needing food. There's several ways of feeding them and one that's super easy and dirt cheap. You can fed them boiled egg yolk. Now this my sound stupid but I've had people ask what kind a egg so many times before. But you use chicken eggs. LOL I'm going to give you alink to how you can prepare them but I never make quit so much of it as in the link.
I take and wet my tumb then rub it str8 on the boiled egg yolk. Then just add what rubs off on my finger to the tank. Being carful not to add to much cause the yolk can sour the water pretty fast. After about 15mins. I take a piece of air line tubing and suck the remainder of the egg yok out of the tank. I always use a white pitcher or white bowl to put the water in cause you will suck some of the fry up in the tube. With the white bowl you can see them really easy ad then I use syringes to remove them from the bowl an place them back in the tank.
Now here's a few links to food and making a brine shrimp hatchery to hatch your own food for them:
Good luck and anything else I can help with let me know. I'm more then happy to help for breeding betta's is my thing i love growing the fry out and seeing if there's one I want to keep or use in my project black vail tail and long fin spices. lOl good luck