logic forms error

hello guys

i have a question about form building. i have NO EXPERIENCE in word press or website design at all. i have asked someone to make a website for me but i am developing the forms myself and he has basically shown me how t build a Logics form.

here is what i am trying to do for example:
user selects catgory, then sub category, then sub-sub category etc till they choose a final choice, eg, Cars, toyota, yaris, then please enter your comment or problem.

here is the problem im havng. once i tested the form, when i make a selection, for example i have chosen cars, toyota, yaris, then i change my mind and want to select cars, BMW, 350, the program still shows the toyota and yaris as being selected. so it has REMEMBERED my selection. the only way i can make it forget is if i go back into cars and unselect toyota manually and unselect yaris manually.

I HOPE THAT MAKES SENSE.

i want the form to forget my selection once i have got out of it? i dont think that makes sense but please ask if you need more clarifications

aslo i wanted an option of a file upload at the bottom of the form, however, when i nsert a file upload section and oreview the form, all the logic doesnt work.

PS I KNOW NOTHING ABOUT LANGUAGE WRITING ETC, I AM ONLY USING THE VISUAL INTERFACE OF WORDPRESS AT THE MOMENT SO IF YOU CAN HELP PLEASE KEEP THIS IN MIND.

thank you for reading