Space Hulk: Tactics

Just like the with the Terminators, you'll access your hand by pressing . Genestealers convert one card into Blips at the start of each turn. (this is optional, but you should do it nearly every time) This will leave you with two cards in hand, which require Menace Points to play. Genestealers earn one menace point each turn, and cards cost between 1 and 3 points.

So you may need to wait several turns converting cards, without playing them. Then when you have enough Menace Points, convert a card, and play the remaining two.

Doable during the Genestealers campaign, from the second mission.
Unlock the card that allows you to spawn two more Blips during the Conversion phase.
Once on the battlefield, and when you get that card in hand, play it with the A button during the first phase (conversion phase) AND convert (with the X button) another card.
End the Conversion phase. Youu should have only one more card in your hand.
During the Action phase, play the last card and you're done.