Bought public IP addresses. Now what?

I'll soon have our organization set up with a couple large Internet connections at two different locations across our city (the primary datacenter will have a 40Gb/s connection and the DR site will have a 5Gb/s connection). Different Internet providers for each connection for redundancy. The end result is to have the DR site be the backup Internet for the primary if the primary Internet connection goes down. We have a 10G WAN circuit between the two sites.

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I've registered an ASN for our organization and we have our own IP address blocks that were recently purchased. We're currently using our ISP's IP addresses for all our public addresses. In brief, what are the next steps to start using our own IP blocks? I assume I need to let our current ISPs know to advertise them for us, but I'm not sure where or who exactly to start with that. We'll be using Palo Alto firewalls on the borders at each site if anyone has any specific advice for them.

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Thanks!