How to unlock a samsung galaxy s6

[lucy.19531910]

A friend of mine gave me this phone and I just set it aside not worried about it now I put it on the charge and sometimes the white screen comes on but it says that the top some kind of code Colonel or something like that

 

[helpstar]

Ask your friend

What exactly does it say? Something like this?
https/www.clangsm.com/forum/uploads/monthly_10_2016/post-45351-1477193532.jpg

Take a picture and upload it to a free image hoster, post the link of it