Depending on how far away they were.
Idk, if they were light years away I guess I'd research more, wait for reports to come in and be really excited
If they came to earth, I'd be honestly quite afraid at first, but eventually see if I could communicate with them some how. Also I'd ring someone and be like OMG ALIENS OR THINGS!!!
If you had to lose either Sight, smell, taste, touch or hearing. Which one sense would you lose?