Backyard fence

I need to get my backyard fence to make it more tighter as it is. By that means less space between the legs of the fence. First for animals not to go in and second very important for my little mini baby doggy to go out. Because he is baby. Unknown what’s best or not. He is very curious to learn explore so it gets into trouble. I buy already A very string and think rope 100ft each. I have 6. I put 1 myself already. But I can’t stand the heat and I am injured. So just need anyone who can help me rope the fence.