As suggested by the other comment, follow BTCsessions npub1rxysxnjkhrmqd3ey73dp9n5y5yvyzcs64acc9g0k2epcpwwyya4spvhnp8 tutorials to get yourself up and running. Regarding your security concerns, i would suggest to use WPA3 wifi secure connection.

Get your node up and running, start by connecting a hot wallet and a cold wallet to your node. Once this is done and you feel comfortable, i would suggest to start playing around with the Lightning Node (slightly more complex than BTC node), open some channels, make some purchases, close channels, reopen channels, etc...

The next step: run your NOSTR relay (very easy) under @umbrel, install Tailscale VPN so you can use NOSTR outside of your local umbrel and your actvity/content synchronises once you get back to your wifi network.

Never put all your BTC funds under your node (use cold wallet) and dont be afraid. Is a fun project with lots of learnings.