Hi,
Welcome to the forum. I am really glad to help you out.
You need to consult a neurologist for the same. You need to undergo a detailed examination which will include checking for the presence of any heart murmurs, presence of any carotid bruits (indicative of the narrowing of the carotid arteries), looking for any abnormal rhythms of the heart.
You will also need to undergo further tests like an EKG, an echocardiogram, a carotid Doppler etc.
Basically, the search is to look for the source of the clot which has entered the brain circulation and caused the TIA or mini-stroke.
You need to be on blood thinners like a low dose aspirin to prevent any future events. I sincerely hope this helps. Take care.