The procedure is explained pretty well here
http://windows.microsoft.com/en-us/windows/fix-corrupted-user-profile#1TC=windows-7
It's the same for 10 as it was back in 7
Ermmm... actually that explanation is comprehensively incomplete, covering only "My Documents" and ignoring Music, photos, favourites etc (OK, easy to work out yourself), not to mention profile settings and bookmarks for such applications as Firefox (harder, and different for each app); also there is a pointless step where it tells you (step 2) to open "My Documents" and then navigate (step 6) to the Documents folder of another user. At best this is confusing.
Also there is no mention of how to deal with the permissions issue: when you attempt to open another user's home folder, Windows (very properly) gets in your way and makes you apply Admin privileges to gain access to it. Once you have gone through that (potentially lengthy, depending on the total number of files) process, writing those files to the *third* user's home folders poses another, related, series of challenges.
A better (in my inflated opinion) method would be to log in as User1 (the profile you want to copy *from*) and copy all the contents of the profile to a staging area - an external disk would probably be best - then log on as User2 (The *to* profile) and copy back. Essentially a backup and restore, which automatically bypasses permissions issues and makes sure to get everything possible. In fact I just use SyncBack, a freeware file backup program to do this with minimal mess and fuss. Takes quite a while, but in the long run I find it's faster than the "official" Microsoft offered procedure.