You have to connect the new light in the same configuration the old one was. If the new light does not have enough space, then you will have to install a weather proof junction box where the light was and run a short cable to where the new light is. This way you have enough room to connect your original two cables and a new third cable to connect to the light.
If it helps, your "problem" is quite common, but being as it is an external light means a weather proof junction box is required if it were indoors other methods are often used.
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