I want to restore my contacts from iPhone 6s

Hello! Let's see if I can help you in doing this :)

The easiest way is to:

1. Go to Settings > [your name] > iCloud.
2. Turn Contacts off and select Keep on My iPhone.
3. Turn Contacts on and select Merge, then wait a little while.

Your old contacts should appear shortly after.

The other way is:

Restore your contacts or bookmarks from an earlier version

1. Sign in to iCloud.com.
2. Scroll down to the bottom of the window, then select Data Recovery.
3. Select Restore Contacts or Restore Bookmarks. 
4. Select Restore next to the date before you deleted the content.
5. Select Restore again to confirm. After the restore completes, you get a notification on iCloud.com and an email at the address on file with your Apple ID.