I’m running Pop os and I can’t download any games to my second hard drive. It says I don’t have permission to and I’ve tried changing the permissions and doing different commands, but none of them have worked. I can write to my normal boot drive but not my 2tb hard drive and they are both ext4 I even tried changing it to fat but didn’t work.
Keep it on ext4. You’re running Linux, not Windows. So you initial choice of filesystem was perfect. 
Your drive is probably still owned by root. You have to take ownership.
sudo chown [user]:[group] /mnt/.../drive
The user and group params are typically your username.
How is you drive mounted? The best way for internal drives is to add a mount point to the /etc/fstab file. This way the drive is remounted to a directory path you defined each time Linux boots.
It just tells me no such file or directory when I use that and the drive is already mounted. I’ve tried mounting and unmounting it. For some reason steam works perfectly fine with downloading to it, but lutris just keeps saying don’t have permission.
Where is your drive mounted precisely? I used the path in the command as an example, you have to put the path to the drive there.
/Home/2tb that’s where it’s mounted at. Sorry I’m pretty new to this and just learning how to do a lot of new things all at once
and my username and group name is just m
okay I think it worked I did sudo chown m:m /Home/2tb and now I can download stuff to it, but it was doing something weird where I could download to it then later it would say I don’t have permission to run it after I restarted and tried starting it.
Don’t worry, you’re doing great.
I think you have to do the chown command recursively. Over all files in that location.
chown -R m:m /home/2tb
Otherwise, when there could be files/directories deeper in the file structure which are still owned by root. When a process wants to access those location you can get permission errors.
Okay I just did it over the whole drive and then I can also do it to one of the folders that I will have all games in