If you can respond quickly, it is common to say, "Just a second". Depending on the length of time, you could also say, "I'll be right there" or "Can you give me a minute?". If you can't help them right away, you could say, "I'll do that as soon as possible". Hope this helps

Hi Fernando! If you don’t want to go immediately when someone asks you to “Come here” you would answer: “ I’ll come later” or “In a minute/moment”. “To go later” is a future act and you would say: “I’ll go later” or “I’m going to go later.” You would use this, for example, if someone had previously (in the past) asked you to go somewhere and you are deciding when to go. I hope that helps and have a nice day!

A little later? You can say '(I'll be there) in a minute!' :)

What was said above and plus: "A little later maybe?" <- sounds kind of impolite imo "Hold on (I'm busy/I'll be there in a minute)"