Sure, it might take some time before you can let your thoughts wander in what is around you, without wondering what is around you. All those thoughts you have about what is around you - the colours, shapes, sounds, scents, even the feeling of sunshine and shade...that is your mind assessing them all as they arrive into you.
Ah, but to follow one train of thought in assessing one particular thing where you aren't 'thinking' but just taking it in, that is where you get to let yourself go into that one particular thing and appreciate it for what it is. I guess one way of describing an aspect of this is to stand over an ant nest and watch as ants go this way and that...watch one ant until your have lost it, then another etc...your focus is on one ant at a time. Then stop focusing on individual ants and try to see the ground with all those ants wandering about as though it were one whole thing, with all those little specks going about their business as one complete organism instead of individual organisms.
When we are in particular surroundings, we take in one or two or several things at a time...but seeing it all as it is, interacting as it does, in one complete picture, that's where you can not lose yourself but immerse yourself into it all. I guess an analogy is: If a tree falls in the forest and no-one is there to hear it, does it make a sound?
Your presence is what hears the sound...sees the ant-community as a whole...feels a city street around you as you drive through it...it all happens whether you are there or not, but to be part of it as it flows about you is the trick. That is the wonder of individual experience as life itself...our little expression composed in individuality that is one grain of dirt compacted to make a mountain protruding from the crust that has hardened above the mantle and all lower layers making our Earth. Everything that exists is but one grain of the entirety...composing the entirety when all grains are put together.
All it takes is a blink of an eye to be separate from it and then part-and-parcel of it...and if you can let yourself go a bit, 'it' will beckon your inner self out into it. And 'it' is you yourself, for you are the only one who sees that you are not all that surrounds you, but you can be...mind merging within with without as though breathing is going from one to the other and neither knows which are the lungs.
Sorry mate...maybe a bit much all at once...but a lot of my writings in here broke it down in parts. Still a bit more to let out but I don't think folk are ready for that...I hint at it in the last paragraph above, but a lot of folk would find it hard to digest.