Design for A5 print ad

We are a speaker agency, booking in inspirational speakers for the corporate market. We do not advertise in print media but a freebie has come up and we need help designing an ad to go into a magazine. Req's below:

An advert in full colour that measures 210mm x 297mm

It will have to have a 3mm border all the way round it as print sometimes trims of some of the original size

Full colour but it needs to CMYK which is a colour system adopted for print

If you can help with the design and delivery of this please get in touch.

Regards

Jason