to stake, just hold your ESP in a wallet ... I use PoSWallet.
just generate an esp address in the dashboard (coming soon with 2.0 update, I already had mine before they disabled wallet address generation).
If you use ESP wallet, it needs to be unlocked to stake ... that is what I heard.
There is nothing definite said on masternodes yet. you can get more answers from
the official Esper Discord, dev channel Q n A every wed night, the dev answers questions live. :)
https://discordapp.com/invite/hhYP8yT