1
She doesn’t works here.
She doesn’t work here.
Does she works here?
Does she work here?
In the present simple, use does or doesn’t + the verb without -s: ‘Does she work?’, not ‘Does she works?’
2
They didn’t helped me.
They didn’t help me.
Did they helped you?
Did they help you?
In the past simple, use did or didn’t + the basic form of the verb: ‘Did they help?’, not ‘Did they helped?’
This also applies to irregular verbs: ‘Did she go?’, not ‘Did she went?’