it may sounds silly, but what exactly does this cue mean when it comes to perform it, ‘‘spread the floor’’? What moves should I have in mind?
Also, when it comes to move the bar with heavier loads, is it wrong to feel working more arms than lats? I mean, for the pulling move to come more from arms than lats… does this mean that form is wrong ?
Spreading the floor has to do weight distribution is your feet. It’s also a cue used in squatting.
For sumo you’re wanting to have the weight shifted towards the outside of your feet. Bringing in your hams and glutes.
There isn’t anything wrong with feeling the movement in your arms, but you should be feeling tension in not only your lats, but throughout your entire body. People refer to it as full body tension. Keep your entire being tight throughout the entire movement.
Keep your shoulders back, lats in your pockets, spread the floor, brace, generate strength from the feet through the legs and glutes, straighten to lockout position keeping your lower back neutral and rigid, and upper body tight.
Imagine you’re trying to rip the floor apart with your feet.
I’ll take a punt and say if you’re feeling your arms work more than your lats something is a bit off, or at the very least your lats are slacking off on you. It could be that with heavier loads you find it harder to keep your lats tight. You might also be jerking on the bar at the start of the lift which increases the risk of a bicep tear, instead of starting with your arms dead straight. All your arms are, are connectors between your back and hands when you deadlift.
I’ll add to what’s been said with how I specifically imagine this cue. There’s no right or wrong way to think of these things as long as it creates the desired effect. I pretend that I’m trying to turn my toes out away from my body, but I don’t let them actually move. It’s like externally rotating your hip without actually moving them. Done right, you’ll feel your glutes and hips get very tight.
Yeah, I mean I feel the total tension you describe but if I had to “measure” it, I’d say that first I feel, legs and then arms… And I thought that supposing deadlift has a lot to do with back, maybe something is wrong with the form, cause other body parts first take charge…
I mean I check my form, my position before starting, not saying I’m 100% right but I think it’s ok 
So if I get it right, I imagine that my feet are “pushing” out, each to the opposite direction but out right ?
Do you have any tip to recruit my lats and generally back a little more?
I think I’ll give it a go in my next session 
Squeeze oranges in your armpits.
Thank you! Hope that’s going to work!
It’ll work.
Try narrowing your cues down to at most three per lift. It makes it easier to get them right. For example, my cues for deadlift are squeeze oranges in my armpits, drop my arse and jump into the pull; for squat, it’s squeeze oranges, make a double chin and open my taint; and for bench it’s heels to traps and pull my elbows outwards.
Bracing isn’t a cue as such but a skill like the lift itself, and can be slightly different for each lift. Some cues will link into bracing (like the oranges one), some won’t (like opening the taint). Get cues and bracing right and the bar just moves.