'Another' is made of the words 'an' and 'other', so it means 'one other' and is used to talk about a single other thing. 'Another' is non-specific, so it can mean 'any other.'
'Other' has two main uses:
1. It is used before a plural noun to describe groups. "(The) other teams are ready to play."
2. It is used with 'the' to refer to a specific singe other thing. "This apple is really sweet. The other one was sour."
'The others' is a collective term that refers to an entire group. "Out of all the people I invited, only one came to my birthday party. I guess the others aren't really my friends."
Here's an example of the difference between 'another' and 'other':
1. This cake is delicious. Can I have another slice?
-This means that any slice of the cake will be okay.
2. This cake is delicious. Can I have the other slice?
-This means that there is only one slice left.
3. This cake is delicious. Are there other slices left?
This cake is delicious. Is there another slice left?
-This shows the difference in singular and plural usage.
My students have a lot of trouble with these words. Remember two key things:
NEVER say, 'the another'.
'Others' and 'the others' are both collective nouns, so don't use them with nouns.
X - The others teams are ready to go.
O - The other teams are ready to go.
O - The others are ready to go.