You just buy LEOM/LEOMM (as you would do with every other token on Hive engine) and stake it (= as LEO)

I see currently LEOM is only available ( don't see LEOMM) on Hive engine and its at the price of 2 hive. So I transfer my hive to Hive engine , buy LEOM , then transfer that to Leo and stake it ?

I have not used Hive engine any time.