>>97394427
Open the bottles and let them sit in a dry room for 24 hours. Citadel paints have a problem with being too watered down.

Take it back and get a better hobby since you're already starting wrong, save yourself the trouble.

>>97394427
Assuming that’s the first kit you got in the pic, use the models it came with to practice. Do each one different to get a feel for the style you like. Use a spray primer to fully coat each model before you paint. Army Painter black/white/grey is a good choice and cheaper. Shake for at least 5 mins before using the first time. Just a light spritz on every side of the model and make sure you get into crevices.

Start “deep” in the model at first. By this I mean details that semi-obstructed or not surrounded by other areas you’ll need to paint later. This way when paint gets on other parts it doesn’t matter because you haven’t gotten to them yet and you aren’t ruining what you’ve already done. You don’t need to let it dry long before adding colors on top. Learn what each type of paint does.
Base paint is thick and for primary colors on the surface of the model.
Layer is thinner than base but still thick enough that it will heavily show through the base and even fully cover it in large amounts.
Contrast is even thinner and used to modify existing base/layer colors. It will make the colors darker/lighter depending on what you’re using but if you use it over the wrong color (ex red contrast on yellow base) it will look weird. You can do this as you play around, but it won’t always work as you want it to.
Shades are super thin and used to give the model a more robust look. Some make them look dirty (Agrax earthshade) and others darker and shinier (nuln oil). You don’t have to use a shade, but many people do a “wash” at the end on each model. You just coat the whole model in the shade and wa la.

>>97394490
This is a clear troll. Citadel paints are thicker. I’d recommend getting a pallet of some sort. Add the paint then add a drop or 2 of water to thin it out. You’ll cover more surface area and it will be more consistent with less brush lines.

>>97394759
Oh and I forgot to add to the paint type list:
Technical paints are usually added to give a texture. The astrogranite in the kit you have has a gritty, cement-like texture to it. You have others like nihilakh oxide which gives it things a kinda dusty, blueish oxidized copper tinge. Blood for the blood god adds a nice realistic blood effect. Get crafty with them. They can be fun.

>>97394427
Happy Birthday
1, The first thing I wish someone had told me is that there is a learning curve before you even have the technique right. I straight destroyed my half of the box set with horrible paint ideas, but it was all learning. If you like the figures, you might want to set one or two aside, paint 99 cent plastic army men or cheap plastic dinosaurs from a toy store for a while, and sort of learn what painting on a 3D surface even feels like.
2. Thin your paints has been memed into tiresomeness here but it is a beginner tip that many beginners still don't hear at first. The GW paints are supposed to be mixed with water, not painted from the pot.
3. If you are unhappy with a paintjob you can always strip it with isopropyl alcohol and an old toothbrush. However, for your first minis in particular, I recommend not doing that, because it's important to see how you've progressed.
There are many many tips and videos, we have an active thread that is nothing but the painting journey. But for beginner tips, I think those three are concise enough.

Don't drink paint water.