Hello! How I can accept NEM stake?
accept? what you mean?
If IPO is closed, how I can owned menstake?
2 weeks after NEM will be started you can exchange tokens to NEM Coins, but if you need token now for AE you mast pm PATMAST3R
But I not have hem stake. What I need do?
don't understand you, what you want, you want to buy some NEM Stakes or what?
Yes
have you invested in NEMs IPO, or you like to buy some stakes with NXT AE?
you want to buy a nem stake? you can buy on the nxt asset exchange.
I want buy menstake in AE, but I not know how do it. I'm lamer

it's easy.
just start NXT client.
open Asset Exchange, and look for NEM asset
https://nxtblocks.info/#section/assets_exchange/12465186738101000735Asset Id: 12465186738101000735
click add new asset