Easy job no more than 5 minutes.
On the Audi a1 forum there is a idiots guide.
But simply remove the leather gaiter, peel away the crimp which holds the gear knob to the stick. Then remove the knob and place new one on, slightly tricky bit is compressing the new crimp but with a good pair of grips with some reach its crimped.
Then push the new gaiter down. Job done no mechanical skills required.