There is a plethora of options for folks to upskill on marketing analytics these days. From TikToks, to online courses, to short courses at universities. An undercooked approach is to create your own side project and play around with different analytics tools. To create your own reports/analysis. And then to go to friends and help them with their side projects. What are they trying to achieve, and how can you help find opportunities for them by analyzing their data. This learning by doing will put you in good stead.
A combination of the two is probably the best bet, but starting with a side project, can be a very easy place to start. With no barriers to entry! Nor cost. It may even lead to some paid work anyway.
Internships are very valuable too, where you can go help out a company on real projects. And ideally get some mentorship and build your own experience. As well as building your network.