How do I change read and write access for a USB drive connected to my Arcadyan gateway?

[Sajal]

I have Telstra Gen2 modem. I have a 1TB HDD attached to the modem which I can access with my TV, Laptop and mobiles. No issue there. Problem is I can not add or remove files from HDD while it is attached to the modem. Is there anyway to enable write and delete permission through modem settings? [I understand the security issue, I still want that option for convenience]

Thanks in advance.

[cf4]

Are you accessing the files on the PC using File explorer using SMB1.0 or are you using a media app such as VLC or Windows Media Player using DLNA?

[Sajal]

I am using file explorer on my laptop. I use BubbleUpnp app for my android phone and Sumsung TV Detect the HDD automatically. As I mentioned earlier, no issue accessing file or device. Trying to find out a way to get write and delete privilege but no luck so far.  

[cf4 · Accepted solution]

The Bubble app uses DLNA so you will not be able to edit files on the Android device and TV. You need a app such as ES File explorer which uses SMB.

On the PC have you enabled SMB1.0 (Turn Windows Features on or off)?