Changing user permissions

This might work
1. List groups from the file /etc/group:
$ cat /etc/group
Let's say I find a group: user1:x:1000:
If I wanted another user to access user1's files I could try...

2. If you have sudo set up use the usermod command like so (very important not to omit the -a as it means 'append' not 'replace.')
$ sudo usermod -a -G user1 user2 (I am putting user2 into the user1 group)

Now user2 is in user1's group

if user1 is not a sudoer then I would have to log in to the root account by

$ su
and enter roots password

then run simply

# usermod -a -G user1 user2

Looking at my Desktop folder by opening a terminal on the Desktop and using
$ ls -als
I see listed (ls) a graphic file: 4 -rw-r--r--. 1 user1 user1 3448 Jun 30 07:51 systemd.svg
-rw-r-r-- means owner (gsmyli) can read and write to the systemd.svg, owner's group can read the file.

If user1 is set up as a sudoer then he can always look at user2's files by using the sudo command.

I am sure's lots of other ways to accomplish what you want.

I'm working on this, it is tedious learning, but perhaps I want a more simple way to do this, if possible? By this I mean working through GUI, making accounts accessible to the sysadmin. right now, my default login is jais as user. I created another account for different work I'm doing, such as a coop, and this is the user newlc. Simply put, how do I get that stupid X off the newlc file image when looking at it in the home file window?

here's how I went about looking at this stuff in the terminal

jais@Ding-bat:/home$ ls
jais newlc terracemill
jais@Ding-bat:/home$ cd newlc
jais@Ding-bat:/home/newlc$ ls
ls: cannot open directory '.': Permission denied
jais@Ding-bat:/home/newlc$ ^C
jais@Ding-bat:/home/newlc$

Do I have to be in a specific directory to run the commands you layed out above?

here's how I input the first commands, let me know what I'm doing wrong.

jais@Ding-bat:~$ sudo usermod -a -G jais:x:1000:jais newlc:x:1002:
[sudo] password for jais:
usermod: group 'jais:x:1000:jais' does not exist
jais@Ding-bat:~$ su
Password:

realize I omitted some colons but still no go

usermod: group 'newlc:x1002:' does not exist
jais@Ding-bat:~$ sudo usermod -a -G newlc:x1002 jais:x:1000:jais
usermod: group 'newlc:x1002' does not exist
jais@Ding-bat:~$ sudo usermod -a -G newlc:x:1002: jais:x:1000:jais
usermod: group 'newlc:x:1002:' does not exist
jais@Ding-bat:~$ sudo usermod -a -G newlc:x:1002 jais:x:1000:jais
usermod: group 'newlc:x:1002' does not exist
jais@Ding-bat:~$ sudo usermod -a -G jais:x:1000:jais newlc:x1002:
usermod: group 'jais:x:1000:jais' does not exist
jais@Ding-bat:~$ sudo usermod -a -G jais:x:1000:jais newlc:x1002:
usermod: group 'jais:x:1000:jais' does not exist
jais@Ding-bat:~$ sudo usermod -a -G jais:x:1000:jais newlc:x:1002:
usermod: group 'jais:x:1000:jais' does not exist
jais@Ding-bat:~$ sudo usermod -a -G jais:x:1000: newlc:x1002:
usermod: group 'jais:x:1000:' does not exist
jais@Ding-bat:~$

I feel like I'm missing something very obvious...

here's what I tried, to no avail. I am logged in as jais, and I would like to place files in newlc's folder.