Respected experts pls tell me something such that I can xpertise in auxiliary words pls giv me som tips on that...... I have practised a lot many exercises and failed to get correct each time... Ther mayb som clues that vil help to recognise the use of correct modals(I know the rules regarding the modals)

'Could' is used to ask for permission: Could I go to the classroom now?
'Should' expresses:
- a condition: If I should collapse, take me to the hospital.
- the likelihood of something: They should be drenched by now.
- a reason(emotional/moral/obligatory) to do something: We should obey our parents.
Some clues for use of modals are:
'Would' is the past tense of 'will', indicates
- an action in the past that happens commonly: She would eat fish daily.
- conditional modal verb: I would eat if I got hungry.
- polite request: Would you consider my proposal?
'Will 'expresses:
- Future tense: I will go home tomorrow.
- determination: They will win the match.
- capability: This bucket will carry twenty liters of water.
'Can' expresses ability: I can swim under water for a long time.