What bike do I need ?
If you want to join a club ride, then you will need a road/gravel bike or a hybrid. If you are buying a bike for the first time, then there is no substitute for going to a bike shop and going for a test ride. Getting the right size of bike is absolutely key, to get this wrong can be an expensive business !
Most bike shops will offer a fitting service or at least give you good advice on the right size for you.
If buying directly from an internet shop then you really need to know the size and geometry that suits your body shape.
The two most important dimensions on a bike are the seat tube height and the top tube length. Note that each brand has its own specific geometry and may differ significantly to another brand. The frame geometry (triangle) is dictated by the lengths of seat tube, top tube and down tube.
Equipment to carry
Carrying a spare inner tube, tyre levers and a pump is essential. All riders will encounter a puncture at some stage. The trick is to be able to deal with it especially if you are riding solo. You need to be self reliant and be able to get home on your own.