Help me to buy a trailer

[Smallstuff]

we have finally decided we need a trailer and Go Outdoors are making us one up!! But what else Do we need?
I guess some sort of electrical bit for the lights? And a number plate but any other essentials!
Have no idea what we are doing?!?!

We've just had our first trip away with a trailer, it was great! You need to get a tow-bar fitted to your car - this costs around £200. There are companies that will come out and fit them while you're at work or you can just take your car to them. Once that's on you just sort of hook the two together, dh did it both times, it was easy.

Then you need a bar thing across the bottom of the trailer which is connected to the lights and has your number plate stuck on. These vary in length, we had to get a new one and it's not quite long enough but ok. Though if you're buying a new trailer it will have one of these I suppose (we got ours from ebay and this bit needed replacing).

Think that's it - a cover in case it rains or stuff blows out but again, if you're buying new perhaps they are included?

Thanks lecce.... We have got halfords making us up an Erde 142.... It has lights etc built in and we have got a number plate to stick on(and some strong glue!)....
Our car has a tow bar but is new and so has a 13 pin electric socket and all the trailers we have seen are 7pin. we got an adaptor from the store and have spent an hour trying to put it in despairing that we would ever do so....no instructions but my brain and DH's brawn finally got it in. Otherwise would have trailer but no electrics!
I have to pick the trailer up on Thurs by myself so hope to goodness the electrics work and I can get it home.....
Also found a cover that looks the right size!!
Beeping exhausted now!!!!
Can I ask what the chain hanging off the towing arm of the trailer next to the bit you attach to the tow ball is for??

Having just bought myself a second hand erde the chain is the safety chain to pop over the tow ball before hitching, so if trailer jumps off it is still attached to your car via the chain, happy camping

Thanks so much pipsy