Even if you do not have entitlement to download, there should be a bit older ADSM version included on the ASAs. There is no extra charge to use that. Check for it by doing a "dir" command and also "show run | i asdm".
Did you buy a Cisco support contract with your new firewalls? That's required to have entitlement to download software updates, including ASDM updates.
Depending on how you ordered them (exact SKU), they may or may not already have the necessary free 3DES-AES license installed on them. That's required because without it, neither your browser (used for first access to ASDM) nor Java (used by ASDM) will negotiate a strong cipher acceptable to any recent browser or Java version. You can check from the console with "show ver | i 3DES".
If you don't have the license, you can get it by going to software.cisco.com and requesting it. No entitlement is required - only a free cisco.com userid and the serial numbers of your ASAs.
If you do not buy any AnyConnect licenses (used for remote access VPN), you may use 2 clients simultaneously with the built-in 2 user license. (Site-site VPNs are included withou the need for additional licenses.)
