Understanding Hot Air Soldering: Use of Flux in Gel, Nozzle Types and Their Applications

Hello, I'm going to learn to solder a bit. Electronics engineer is coming and they don't teach such things in college I just bought a Hot Air soldering station and I have no problems with soldering with a soldering iron, but I got lost with hot air soldering. I've seen a lot of video tutorials where some solder paste is applied to the pads, then a little magic with air and it's done. I got some flux in gel with flux in the set with the station and I have no idea what it is for. Is that the paste? It looks a little different.

The second thing is the nozzles. I got 8 of them. 3 round, 3 edged, 1 square and one thin round bent at an angle. Could someone briefly explain which nozzle is best for which systems?

ps please don't yell at me too much if this has already appeared on the forum, I've been looking for 3 days, reading, browsing but I couldn't find answers to my questions.

Pasta and Flux are the same.
The description of the HotAir soldering iron tips is not very precise.
Post pictures, it will be much easier to help.
I have these attachments, but their uses are different.
Some for soldering are better, others for desoldering.

The nozzles look something like this.

There's another round one I've put on for testing purposes now. It looks the same as the two middle ones on the right, only it has a slightly smaller diameter

And as for this flux, I understand that it is the only thing I need for SMD soldering? I put on, put the element and solder with air, right? I've seen some solder pastes with powdered tin. I don't need one to start with?

Pasta and Flux are different. The paste that is used to make "magic mary" by applying to the pads is a paste with tin, e.g. KOKI, KEDA. It is powdered tin in the form of a paste that is applied and heated to obtain solid tin.

Flux is a flux that makes soldering easier. It is applied to the tin.
The flux fulfills three functions:

-removes oxides and other impurities from soldered surfaces
-prevents the formation of new oxides during soldering by cutting off contact with air
- facilitates melting and increases the fluidity of the solder

Paste and flux, a matter of terminology.
Description depends more on consistency.
For tin, the manufacturer of my soldering station used the familiar sounding phrase "tin in gel".
As for the endings, it can be said that:
1. From the top right PLCC desoldering
2. Bottom right HotAir soldering
3. HotAir soldering on the left, but the edges of the PLCC circuits.

It's a bit difficult for me to define the methods of working with this type of soldering iron.
Mine has over 30 specialized hot air nozzle caps.
The set also includes a soldering iron with replaceable tips, a suction cup for lifting desoldered SMD components and a suction nozzle with nozzles of various diameters.
Just start using and don't worry about our advice.
Certain operations can be performed by a tool not entirely intended for this purpose, but after all, these tools are for you.
:D

Flux is enough to get you started.
If you have it in something like a syringe, then if it's runny, it's a good idea to attach a short, thin injection needle at the end for precise dosing and to prevent drying out if you forget to seal it.

ok thanks for the replies. Just one more question about paste and flux. Tin paste also has flux in it, right? At least that's what I found in stores. So it's like tin in a wire that already has rosin in it? So in what practical situations is flux used? I use such an additional rosin by dipping the tip in it when I want to solder some larger things, e.g. power sockets. Flux is used similarly? i.e. I also put it on the pads next to the tin paste to make it solder better? Or do I melt it on the pads before I even place the element there? Or do I not need to use it at all and just buy tin paste?
I'm asking because I want to learn how to solder properly as befits a future engineer, and not to be ashamed to eat while defending my thesis

Tin paste has flux in it.
I use Flux for the case
1. I desoldered something and did not clean the pads thoroughly. Then I put a new element on the board, "attached" it to the board for 2 February diagonally, cover it with flux around (to save only on the pads and a thin layer - that's what the syringe is for) I press in the middle system and solder around with hot air.
2. Something needs to be desoldered from the board, and the paths are delicate. Then I coat it with flux and heat it.
3. Desoldered system and cleaned pads. Then I put a drop of flux on each pad, put the system and after a slight heating (flux like water) the system positions itself. I hold this system in the middle with something (so it wouldn't move) and I continue to solder in a classic way.

Okay, I more or less understand. For now, thank you for the answer, soon I will bully the old graphics card a bit and see how it turns out in practice.