First things first: Coolant level, is the most URGENT AND IMPORTANT part that one shud never ignore or prolong.
For coolant level check, there is always two way check that you need to do. Once in the morning when car is cold, check the level at bottle, then start the car and wait for 5 - 10 mins when car reaches optimum temperature. The level should stay same without any noticeable difference. If there is any difference in level then wait until it cool down and then add coolant, litle bit extra, so that it can overflow and reach to ideal level when car is at ideal temp.
Checking for other leaks in line to transmission cooler or radiator is good practice, so that it doesn't loose coolant over period of days. Get those leaks fixed asap and keep monitoring the coolant bottle level as a regular safety check.
Washing in the engine, is best done with steam not with water. Or even better is with diesel spray, but you should have time to let it dry completely otherwise diesel wash will be like dust magnet. With any engine bay wash, one should cover alternator, fuse box, and ECU side completely with plastic and avoid splashing water around it.
Airbag light is known error in almost all LR, that yellow socket under driver seat need to be properly secure with tape or cable tie or else with every extreme full front or full back move you will have this light.
Another important thing for you to remember as a new Landie owner. If you see "Gearbox faulty" then dont panic its an indication of weak battery, as electronic gear oil need regular volt from battery and slight disturbance in volt supply show this message.
If its a high mileage car you got, better check all fluids condition or even better to change all diff fluids, coolant, brake oil once right now so that you can monitor there life and kms driven. All fluid change might cost you around 500 - 1000 dhs but it will save lot of future confusion and chances of failure. Also remember to go for semi synthetic engine oil or normal mineral oil and change at 5k - 3k period than fully synthetic, because in fully synthetic you might end up in oil leaks and spoiling your parking bay. In landies all oil seals are very prone to leak and less forgiving than toyota and nissan, so thinner the oil easier it will leak.
Good luck with new ride and have fun with it and welcome to the Land Rover owners club.....!