If Specify the Amount is selected, a text-box field should be filled mandatorily. Then the user shouldn't be able to select other options ($1, $2, $5, $10, Revoke).
If the user selects $1, $2, $5, $10, Revoke then the text-box field for the Specify the Amount should be disabled to enter information.
Also, there is another text-box field for one-time donation which should be mandatorily filled by the user if he is not choosing the above 6 options.
New to InfoPath, please be gentle on me and kindly guide me step by step.