The steps for setting up a seed node are pretty much the same as setting up a witness node. Instructions for that are here: https://steemit.com/witness-category/@timcliff/steps-for-setting-up-a-witness-node-the-manual-way

The main differences with a seed node are:

• You don't configure the witness name
• You don't configure the private key
• You enable p2p-endpoint = 0.0.0.0:2001

If/when you setup a node, be sure to come to the #steed-nodes channel in steem.chat to let us know.