1. Go here:
http://www.insolvency.gov.uk/
It is the website of the Insolvency Service & has a lot of factual info.
2. If you know nothing about bankruptcy, it is best to get some free advice - contact your local CAB or phone CCCS. Do not get involved with any of the outfits that advertise they can help you with this - they charge fees for something you can do yourself with some free advice. (I do not thinbk your local County Court is likely to be able to give you all the advice you need, although you do need to get the forms from them.)
3. The cost of going bankrupt is £700, but if you are on a low income you might be exempt from the Court fee element, which is £175. Sometimes it is possible to get help from charities with the fee - CAB can advise on this.
4. If you already have a basic bank account you might be able to keep it, but the only banks which say specifically that they give basic accounts to bankrupts are Barclays and Co-op. So you might have to change the account. You can do this before going bankrupt if you want - but let the new bank know what you plan to do & get them to confirm you can keep the account after bankruptcy.
5. Unless you are in a sensitive job (e.g. one where you are controlling cash, or acting as an accountant) there should be no impact on your employment. It is possible your employer will not even know about it.