This is a popular question here on the forum:
User access is a completely different plugin. Much more complex and specific (multiple access levels, privileges, etc).
This requires either a compatible plugin (but Lana Downloads Manager is simple and single purpose plugin) or a freelance developer to create the custom code.
So this is not possible with Lana Downloads Manager alone. You need to add a user manager plugin. Unfortunately, I currently have no information that any of the user management plugins are compatible.
If you want to use Lana Downloads Manager and want user restrictions, then I suggest you hire a freelancer who can code for you. If it’s not complicated, it’s a few hours of work.
Or as far as I know (although I haven’t tested it), this plugin also handles user roles: https://www.ads-software.com/plugins/download-manager/
Thank you for your understanding, I hope I could help. If you have any questions, feel free to contact me.