I just booted with a new temporary ID and it took 50 seconds to generate the cryptographic key. After 3-4 minutes, Urbit had bootstrapped itself and was accessible over HTTP.
You can try with these commands, using Mac in this example:
mkdir urbit
cd urbit
curl -JLO https://urbit.org/install/mac/latest
tar zxvf ./darwin.tgz --strip=1
./urbit -c mycomet
You can try with these commands, using Mac in this example: