Welcome to the succulent family! I know there are many ways to grow healthy succulents but if you are a newbie, why not read more articles about on how to grow not kill your succulents.
Always remember that:
Succulents ≠ Houseplants.
They are desert plants and if you want to grow them properly, you just have to replicate the desert climates.
Beginner Level: try not to kill the succulent
If this is your goal, the most important thing to know is DO NOT OVERWATER!
I could not stress enough that overwatering will 100% kill your succulents. Succulents are super drought-proof. In fact they are so used to being around dry environment. You should only water around the plant (not directly) when the soil is dry. You can use chopstick or moist detector (highly recommended for beginner) to insert into the pot and if there isn't any soil bits coming out, then it's ok to water them.
Secondly, depending your preference you can grow them indoor or outdoor but they definitely need sufficient sunlight. If you decided to grow them as indoor plant, try to put them near the window sill, despite they do need UV (which mostly blocked by the windows) but at least they do get some sort of sunlight. Bear in mind that if your heater is underneath your window, please do not put any plants there. They do not do well with the cold draught and the heat at the same time as this would create humidity and cause the succulent to rot. Succulents prefer dry environment.
Thirdly is the type of pots. Terrarium might be a trend but the problem is the they do not have enough drainage hole instead the terrarium will trap the water (unless you are pro and master in water control) and again kill your succulent. If you insisted on growing them in the terrarium, I would say at least add a layer of charcoal to the bottom of part to absorb the excess moist. Otherwise, I would recommend the terracotta pot with drainage hole is ideal for beginner as the pot itself is quite ventilated and if you overwater them you will notice the colour of the pot will be darker (that's when you know you need to stop)
The last one is the soil. Succulents hate to be trapped with overly moistened soil. Majority of the soil (even those special cactus soil) is mainly compost with little grit and sand. For me, I would buy extra bag of Perlite or Vermiculite (Wilko is the cheapest but you get from B&Q too) to mix with the compost and clay pebbles to the bottom layer of the pot. You can decorate the top layer with stones or grits. Ratio could b 1:2.1
Once you mastered all the above and looking to grow your succulent to advance level, you can check the next article.
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Please note that the article above is from my personal experience and I know there are many ways to grow healthy succulents. Happy Growing!