Firstly CTRL + ALT + DEL still works just like is has done since 1993, assuming you have a keyboard I think that’s the easiest solution this typically works exactly the same on any PC with any almost any version of Windows. However if you would prefer to use a mouse (or touchscreen), follow the screen shots below:

Click on start button (see 1 below)


Click on the username of the signed in user (see 2 below)


See screen shot below; Lock the PC (3), Sign out (4), or to switch users, click on the username you would like to switch to, in this example itsupport is switching to the user Bob Smith.