Please correction my sentence

1.Are you busy with someone ?
2.Today will you come to my office?
3.I'm waiting here just only for you.
4. I've just finished my lunch.
5.Have you finished your lunch?
7.when will you come to your office ?
8. before 20 minutes when you come here? Did you come here 20 minutes ago? (??)
9. You have to find the easiest way to find the solution.
10.I want to talk to you for just only  2 minutes to find some solutions.\

Thanks.