When studying Meditation in the context of a Buddhism, sooner or later you will encounter the term Jhana. When the mind is composed, collected, and concentrated, this is samadhi; the trance-state that comes from this concentration is called jhana.
Once the body is calmed and the mind is focused, as the mind becomes increasingly concentrated and distractions fade away, you'll notice a feeling of pleasure begin to arise in the body. Pay attention to this feeling. As this feeling starts to grow and your relaxation/concentration keep steady or continue growing, your mind is entering the jhana state. If distractions start coming back, go back to your original meditation object a while longer, then try again.
From AN 5.28 of the PaliCanon:
Firstly, a mendicant, quite secluded from sensual pleasures, secluded from unskillful qualities, enters and remains in the first absorption. It has the rapture and bliss born of seclusion, while placing the mind and keeping it connected. They drench, steep, fill, and spread their body with rapture and bliss born of seclusion. There’s no part of the body that’s not spread with rapture and bliss born of seclusion. It’s like when a deft bathroom attendant or their apprentice pours bath powder into a bronze dish, sprinkling it little by little with water. They knead it until the ball of bath powder is soaked and saturated with moisture, spread through inside and out; yet no moisture oozes out. In the same way, a mendicant drenches, steeps, fills, and spreads their body with rapture and bliss born of seclusion. There’s no part of the body that’s not spread with rapture and bliss born of seclusion. This is the first way to develop noble right immersion with five factors.
Furthermore, as the placing of the mind and keeping it connected are stilled, a mendicant enters and remains in the second absorption. It has the rapture and bliss born of immersion, with internal clarity and mind at one, without placing the mind and keeping it connected. They drench, steep, fill, and spread their body with rapture and bliss born of immersion. There’s no part of the body that’s not spread with rapture and bliss born of immersion. It’s like a deep lake fed by spring water. There’s no inlet to the east, west, north, or south, and no rainfall to replenish it from time to time. But the stream of cool water welling up in the lake drenches, steeps, fills, and spreads throughout the lake. There’s no part of the lake that’s not spread through with cool water. In the same way, a mendicant drenches, steeps, fills, and spreads their body with rapture and bliss born of immersion. There’s no part of the body that’s not spread with rapture and bliss born of immersion. This is the second way to develop noble right immersion with five factors.
Furthermore, with the fading away of rapture, a mendicant enters and remains in the third absorption. They meditate with equanimity, mindful and aware, personally experiencing the bliss of which the noble ones declare, ‘Equanimous and mindful, one meditates in bliss.’ They drench, steep, fill, and spread their body with bliss free of rapture. There’s no part of the body that’s not spread with bliss free of rapture. It’s like a pool with blue water lilies, or pink or white lotuses. Some of them sprout and grow in the water without rising above it, thriving underwater. From the tip to the root they’re drenched, steeped, filled, and soaked with cool water. There’s no part of them that’s not spread through with cool water. In the same way, a mendicant drenches, steeps, fills, and spreads their body with bliss free of rapture. There’s no part of the body that’s not spread with bliss free of rapture. This is the third way to develop noble right immersion with five factors.
Furthermore, giving up pleasure and pain, and ending former happiness and sadness, a mendicant enters and remains in the fourth absorption. It is without pleasure or pain, with pure equanimity and mindfulness. They sit spreading their body through with pure bright mind. There’s no part of the body that’s not spread with pure bright mind. It’s like someone sitting wrapped from head to foot with white cloth. There’s no part of the body that’s not spread over with white cloth. In the same way, they sit spreading their body through with pure bright mind. There’s no part of the body that’s not spread with pure bright mind. This is the fourth way to develop noble right immersion with five factors.
Furthermore, the meditation that is a basis for reviewing is properly grasped, focused on, borne in mind, and comprehended with wisdom by a mendicant. It’s like when someone views someone else. Someone standing might view someone sitting, or someone sitting might view someone lying down. In the same way, the meditation that is a basis for reviewing is properly grasped, focused on, borne in mind, and comprehended with wisdom by a mendicant. This is the fifth way to develop noble right immersion with five factors.
When the noble right immersion with five factors is cultivated in this way, a mendicant extends the mind to realize by insight each and every thing that can be realized by insight; and they are capable of realizing those things, since each and every one is within range.