How To: Mount SMB Shares on a Pi

https://linuxize.com/post/how-to-mount-cifs-windows-share-on-linux/

tl;dr (assuming user/share is set up on freenas)

1. Install cifs-utils and create your mount directory

2. Create a credentials file /etc/win-credentials-app

3. Populate with username= and password= on two lines in plaintext (scary, I know)

4. Chown root: and chmod 600 to have a thin veil of security

5. One-off mount:
sudo mount -t cifs -o credentials=/etc/win-credentials-app,dirmode=0755,uid=1000,gid=1000 //freenas.lan/app /app
Replace win-credentials-app with your credentials file and 1000/1000 with your user's user/group IDs.

6. Auto-mount: (add to /etc/fstab)
//freenas.lan/app /app cifs credentials=/etc/win-credentials-app,file_mode=0755,uid=1000,gid=1000 0 0

7. Will mount automatically on boot. Use sudo mount /app or sudo umount /app to manually mount/unmount with an fstab entry.