you would likely have to do it yourself -or advertise for a local inventor type person to assist. depending on your invention, perhaps an expert in electronics would be helpful & could become a partner - they will be able to get the thing to actually work.
you must organise funding -perhaps ask for sponsorship from a local relevant company who'd want the rights to produce the item once you have got it going.
be careful not to tell them how you intend to make the item, just what the item is -its ok to say " a machine that can turn cotton wool into detergent" because that doesn't give the game away of how its done -thats your power.
you may have to self fund most of it i am afraid, get a loan, borrow whatever, though the prototype just has to work - it doesn't have to look good or be manageable -that can be worked on later -if you can show a company this prototype, this is whn they will perhaps buy the rights.
also if you can enlist a partner with various skills they may be able to thrash out the designs on paper, technical plans and theory - which will explain everything -though with this ther is a risk of theft.
i woul dsuggest doing some kind of mini course or buying an extensive book on patent law, business dealings, contract etc - & consult a lawyer - because if these companies suss out that you are new to this they may sting you.
the patents office will be able to help check out existing patents but their may be a fee -i think to register your own designs there is a fee too.
as i say the best route at this moment is amateur local enthusiasts & inventors i think -& get it all in writing and a contract etc so they cannot steal it either
also do the old post it to yourself, or take a photo beneath the bank clock holding the designs, just as extra back up
as long as any partner you have is aware you have made a lot of effort to