Can someone please explain the new gyms and raids please? I haven't visited a gym before.
Gyms now have 6 slots (more gyms were added to the game to compensate the loss of 10 slot gyms). If the gym is already your teams and there's a free space, you don't have to battle, you can just add one in.
You can get a maximum of 50 coins a day which is usually earnt after 8 hours. If you have more than one Pokemon come back from a gym in a day and you've already hit your 50 coin limit, you won't earn anything.
Pokemon only come out of a gym when battled, not from low motivation.
Fighting gyms is similar, but the longer a Pokemon is in a gym the less motivation it has (the little heart above it's head). However, people can feed them berries to up their motivation. The less motivation a Pokemon has, the easier it is to take down.
You can also now spin all gyms like PokeStops, and if it's your teams, you get bonus items.
Raid battles! A Pokemon will appear above a gym counting down to when it ends. The Pokemon above said gym is the Pokemon you will fight and have a chance to catch if you defeat it.
Currently, you get a 2 hour window, but that might change after Legendaries disappear. During that two hour window you can spend a raid pass (you get 1 free raid pass every day from spinning a gym) and fight the boss as many times until you defeat it. Once defeated, it can't be fought again.
The little heads on a raid determine how easy it is.
Level 1 raids (one head) can be soloed.
Level 2 raids (two heads) can be soloed if you have the right Pokemon with the right type and movesets and you're a high enough level.
Level 3 raids (three heads) need 3 - 4 people.
Level 4 raids need 8 - 9 people.
Level 5 raids (legendary raids) need at least 7, but can need up to 12 - 14 people (Lugia!) depending on the legendary.
Only after you spend your raid pass can you see who else is in the lobby, which is really annoying. So my suggestion is don't spend your raid pass unless you see other people about and they're looking like they want to raid too. Otherwise you'll waste your raid pass and you can't get it back!
Once in the lobby you get 120 seconds to pick your Pokemon (never go with the suggested line up and never use Blissey in a raid battle!).
Check your local facebook to see if there's a group in your area. My town has a WhatsApp group where we organise people for raids and meet to make sure we have enough.
Once defeated, you get rewards (rare candies, golden razzberries, charge and fast TMs, revives and lots of experience)and then you get a chance to catch it.
How many premier balls you get depends on gym control (who owns the gym), how much damange you and your team did etc. More balls = more chances.
Once the balls are gone, the Pokemon runs away and you've lost your chance to catch it.
Hopefully that explains the majority of it! I've probably missed stuff out but there's a lot to learn
If you have any questions, please do feel free to ask